Electron spin wave multiplexing device

Abstract

The present invention comprises: an introduction section that has a first solid-state device having a semiconductor quantum well structure, and into which a plurality of electron spin waves are introduced; a modulation section that has a second solid-state device having a semiconductor quantum well structure connected to the introduction section, and synthesizes the electron spin waves from the introduction section to generate multiple electron spin waves; and a separation section having a third solid-state device having a semiconductor quantum well structure connected to the modulation section, the multiple electron spin waves synthesized in the modulation section being introduced in the separation section, the separation section separating the plurality of electron spin waves from the multiple electron spin waves. The modulation section has the function of superposition of the plurality of electron spin waves by controlling the amplitude, phase, and polarization degrees of freedom of the electron spin waves using the permanent spin-swirling state in the crystal orientation dependence of the effective magnetic field due to spin-orbit interaction generated in the semiconductor quantum well structure.

Description

[Technical Field]

[0001] The present invention relates to an electron spin wave multiplex transmission device. [Background technology]

[0002] In modern society, opportunities to handle large amounts of information are increasing, with the advent of 5G (fifth generation mobile communications systems), AI (artificial intelligence), and IoT (Internet of Things). Light is currently the primary means of transmitting this information, with long-distance, high-capacity transport achieved through optical fiber. Light waves are characterized by parallelism (they do not interfere with each other) and multiplicity (they can be superimposed). Wavelength Division Multiplexing (WDM), which applies these properties, has made it possible to simultaneously transmit multiple pieces of information over a single optical fiber.

[0003] On the other hand, in electronic devices such as semiconductor integrated circuits, it is, in principle, impossible to transmit multiple pieces of information simultaneously. This is because the properties of electrons are significantly different from those of light, making it impossible to incorporate parallelism or multiplexing. However, if electronic devices that also possess the characteristics of light could be realized, it may be possible to realize a diverse information processing platform on a single information carrier, by incorporating the coexistence of analog and digital signals and combining von Neumann and non-von Neumann computing. Therefore, the inventors believe that "electron spin waves" can be used as this ultimate information carrier.

[0004] Electron spin waves can be generated by the effective magnetic field generated by the spin-orbit interaction present inside a semiconductor. For example, there are two types of spin-orbit interactions in a III-V semiconductor quantum well structure: the Rashba spin-orbit interaction (the clockwise arrow in Figure 6(a)) and the Dresselhaus spin-orbit interaction (the arrow in Figure 6(b)). When these two effective magnetic fields are equal, the direction of the effective magnetic field is oriented in one axis direction (arrow shown in Figure 6(c)), and the effective magnetic field direction is fixed to one direction, suppressing spin relaxation. This state can be called a permanent spin rotation state. As the electron spin rotates around this effective magnetic field, waves of electron spin are generated as shown in Figure 7. In Figure 7, λ + =+(1 / q0). In Figure 7, q0 represents the wave number specific to the material. By satisfying this condition, electron spin waves can exist stably in the semiconductor, making it possible to create information carriers that use electron spin waves.

[0005] An electron spin wave is a phenomenon in which the spin of an electron, which has the magnetic properties of an electron, propagates through space while changing direction, and has the properties of a classical "wave." As shown in Figure 7, the length of one rotation it takes for the upward spin direction to change from downward to upward again can be defined as the wavelength λ of the electron spin wave. This wavelength can be used as information, and by treating different wavelengths as different information, it is possible to transmit multiplexed information using electron spin waves. Therefore, information as light waves can be directly transferred into a solid.

[0006] Since electron spin waves can exist stably in a state where spin relaxation is suppressed, it is thought that they can propagate over long distances and that their wavelength can be freely controlled depending on the strength of the effective magnetic field. Furthermore, it is thought that superposition of electron spin waves will be possible by controlling the amplitude, phase, and polarization degrees of freedom. In other words, since electron spin waves have the same properties as light, it is thought that multiplexed transmission of information, which has previously been achieved with optical fibers, will also be possible with solid-state electronic devices.

[0007] The present inventors have previously studied the above-mentioned electron spin waves, and have published part of the research results on electron spin waves in Non-Patent Document 1 below. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] Y. Kunihashi, M. Kohda, J. Nitta, et al, “Drift transport of helical spin coherence with tailored spin-orbit interactions”, NATURE COMMUNICATIONS, Published 8 Mar 2016. Summary of the Invention [Problem to be solved by the invention]

[0009] One problem with the WDM method mentioned above is that the more information to be transmitted simultaneously, the more photoelectric conversion devices must be prepared, raising concerns about increased volume and power consumption.In contrast, a transmission method using electron spin waves is thought to be able to generate multiple spin wave signals by directly transferring multiple optical signals to semiconductors, making it possible to seamlessly realize parallel information processing. This will make it possible to suppress an increase in the number of devices, and is expected to lead to increased speeds due to the parallelism and multiplexing of waves.

[0010] In today's information system infrastructure, the highly efficient control and ultimate utilization of information carriers of light, charge, and spin for communication, calculation, and recording support the information society. Specifically, information processing processes a vast amount of information compared to sequential information processing based on binary logic circuits using 0 and 1, and information is recorded by recording the information of 0 and 1 as magnetization (spin) up and down. Optical communications is the only technology that uses the wave properties of light to multiplex and transmit information. However, the qualitative differences between the different information carriers create bottlenecks in the mutual conversion of information. For example, the wave properties of light cannot be transferred to the particle properties (electric charge) of electrons. As a result, with the explosive growth in communication capacity expected in the future, information transmission is possible through information multiplexing, but since information processing requires sequential calculation of all multiplexed information, a huge amount of information equipment is required, resulting in serious increases in power consumption.

[0011] To solve the problems caused by the qualitative differences in information carriers, specifically the difference between the wave nature of light and the particle nature of electrons, we need a new information carrier that can move away from sequential computation and share information at a high level across the entire system. To achieve this, we believe that we can achieve high information density by utilizing information carriers with wave properties, which we can refer to as wave information carriers here, and taking advantage of the parallelism and multiplexing properties of waves. Furthermore, by using wave information carriers for all communication, processing, and recording, we believe we can seamlessly realize the mutual conversion of multiplexed information and build a new information system infrastructure that can handle huge amounts of information.

[0012] The present invention has been made based on the background explained above, and aims to provide an electron spin wave multiplex transmission device that uses electron spin waves and can handle continuous changes in spin direction accompanying spin rotation as analog signals, thereby enabling simultaneous processing of digital information and analog information. [Means for solving the problem]

[0013] (1) The electron spin wave multiplexing transmission device of the present invention comprises an introduction section having a first solid-state device with a semiconductor quantum well structure, which combines multiple electron spin waves to introduce a multiple electron spin wave, a modulation section having a second solid-state device with a semiconductor quantum well structure connected to the introduction section, which modulates the multiple electron spin wave from the introduction section, and a third solid-state device with a semiconductor quantum well structure connected to the modulation section, which is further characterized by comprising a recording section into which the multiple electron spin waves that have passed through the modulation section are introduced and which has multiple recording magnetic materials for non-volatilely recording information contained in the multiple electron spin wave, and wherein the modulation section is a modulation section that has the function of controlling at least one of the amplitude, phase, and polarization degrees of freedom of the electron spin wave by utilizing the permanent spin rotation state in the crystal orientation dependence of the effective magnetic field due to spin-orbit interaction generated in the semiconductor quantum well structure.

[0014] (2) In the electron spin wave multiplex transmission separation detection device described in (1) of the present invention, it is preferable that the solid-state device having the semiconductor quantum well structure transmits electron spin waves of a wavelength equal to a specific wavelength uniquely determined by the strength of the spin-orbit interaction, and eliminates electron spin waves of a wavelength different from the specific wavelength uniquely determined by the strength of the spin-orbit interaction, thereby allowing the solid-state device to transmit only electron spin waves of a specific wavelength. (3) In the electron spin wave multiplex transmission device according to the present invention described in (1) or (2), when the number of electron spin waves is large, it is preferable that the device be provided with a function to perform a fast Fourier transform on the data obtained by real-space measurement to convert it into wave number space data and analyze it.

[0015] (4) In the electron spin wave multiplexing transmission device according to any one of (1) to (3) of the present invention, it is preferable that the modulation section comprises one or more of a gate electrode for applying voltage, a ferromagnetic layer for spin injection and amplification, and a wiring coupling section for coupling the electron spin wave. (5) In the electron spin wave multiplex transmission device according to any one of (1) to (4) of the present invention, it is preferable that the recording magnetic material having a base magnetic layer and a recording magnetic layer is arranged in a plurality in the recording section, the base magnetic layer is a magnetization reversal layer that excites magnons by the electron spin waves and resonates with the excitation of the magnons to reverse its magnetization, the recording magnetic layer reverses its magnetization in response to the magnetization reversal of the base magnetic layer, and has the function of non-volatilely recording information of the multiple electron spin waves with this magnetization reversal, and the information of the multiple electron spin waves is recorded as multiple states by the arranged plurality of recording magnetic materials.

[0016] (6) In the electron spin wave multiplex transmission device according to any one of (1) to (5) of the present invention, it is preferable that a gate electrode for applying a voltage is provided in the modulation section to form a collective difference gate. (7) In the electron spin wave multiplex transmission device according to any one of (1) to (6) of the present invention, it is preferable that a collective generation gate is configured by providing a ferromagnetic layer for spin injection and amplification in the modulation section.

[0017] (8) In the electron spin wave multiplexing transmission device according to any one of (1) to (7) of the present invention, it is preferable that a wiring coupling section for coupling the electron spin waves is provided in the modulation section to form a set sum gate. (9) In the electron spin wave multiplex transmission device according to any one of (1) to (8) of the present invention, it is preferable that the introduction section has a function of generating the multiple electron spin waves by irradiating a laser on which information of a multiple polarized beam for optical communication is recorded, and has a multiple information transmission function by writing information corresponding to the multiple polarized beam for optical communication into the multiple electron spin waves.

[0018] (10) In the electron spin wave multiplexing transmission device according to any one of (1) to (5) of the present invention, it is preferable that a parallel computer is constructed including the collective difference gate according to (6), the collective generation gate according to (7), and the collective sum gate according to (8). (11) In the electron spin wave multiplex transmission device according to any one of (5) to (10) of the present invention, it is preferable that a plurality of recording magnetic bodies are provided in the vertical and horizontal directions of the surface of the recording section, and that each of the recording magnetic bodies generates a spin transfer effect by spin pumping from the multiple electron spin waves, and has a function of resonant switching.

[0019] (12) In the electron spin wave multiplex transmission device according to the present invention described in (11), when the magnetization of each of the recording magnetic materials is oriented within the film plane, it is preferable to adopt a structure that exhibits angle dependence due to the planar Hall effect, and have the function of reading information in the recording section by reading the in-plane magnetization in the formation area of ​​the recording magnetic material. (13) In the electron spin wave multiplex transmission device according to the present invention described in (11), when the magnetic recording materials are magnetized perpendicular to the film surface, it is preferable to adopt a structure that exhibits the anomalous Hall effect and have the function of reading information in the recording section by reading the perpendicular magnetization component in the formation area of ​​the magnetic recording materials. [Effects of the Invention]

[0020] The present invention can provide an electron spin wave multiplex transmission device capable of multiplexing and transmitting electron spin waves by controlling the amplitude, phase, and degree of polarization freedom of the electron spin waves. Each multiplexed electron spin wave contains continuous analog signal information such as amplitude and phase in addition to digital signal information of 0 and 1 due to up and down spins, making it possible to process both digital and analog information simultaneously. This makes it possible to provide an electron spin wave transmission device and signal processing device that can switch between von Neumann and non-von Neumann type computation. [Brief explanation of the drawings]

[0021] [Figure 1]1(a) shows spin waves generated by Monte Carlo simulation, where FIG. 1(a) is a diagram showing a first example of the spin distribution of up spins and down spins in real space, FIG. 1(b) is a diagram showing the state after applying a Fourier transform to the state shown in FIG. 1(a), FIG. 1(c) is a diagram showing a second example of the spin distribution of up spins and down spins in real space, FIG. 1(d) is a diagram showing the state after applying a Fourier transform to the state shown in FIG. 1(c), FIG. 1(e) is a diagram showing a third example of the spin distribution of up spins and down spins in real space, and FIG. 1(f) is a diagram showing the state after applying a Fourier transform to the state shown in FIG. 1(e). [Figure 2] This figure shows the excitation of spin waves at time 0 with a wavelength equal to the intrinsic wavelength (λ0 = 9.0 μm) uniquely determined by the strength of the spin-orbit interaction in a solid, and shows the case of stable long-wavelength spin waves. [Figure 3] This figure shows spin waves excited at time 0 with a wavelength (λ0=4.5 μm) different from the intrinsic wavelength (λ0=9.0 μm) uniquely determined by the strength of the spin-orbit interaction in the solid, and shows the case of unstable short-wavelength spin waves. [Figure 4] FIG. 1 shows the time evolution of spin distribution when spin waves of different wavelengths are incident on the same solid. [Figure 5]This figure shows drift transport of multiple spin waves and electron spin wave filters. Figure 5(a) is a cross section at Y=0 of the real space distribution of the multiple spin waves shown in Figure 5(b). Figure 5(b) is a diagram showing the real space distribution of multiple spin waves with three wavelength components, λ1=20μm, λ2=6.7μm, and λ3=3.3μm. Figure 5(c) is a diagram showing the reciprocal space distribution of multiple spin waves with the same three wavelength components. Figure 5(d) shows the drift transport in the +Y direction when the multiple waves shown in Figure 5(b) are incident on a region where λ2 is stable. Figure 5(e) shows the state where the multiplexed waves shown in Figure 5(c) are incident on an area where λ2 is stably present and are drift-transported in the +Y direction for 1 ns, Figure 5(f) shows the state where the multiplexed waves shown in Figure 5(b) are incident on an area where λ3 is stably present and are drift-transported in the +Y direction for 1 ns, and Figure 5(g) shows the state where the multiplexed waves shown in Figure 5(c) are incident on an area where λ3 is stably present and are drift-transported in the +Y direction for 1 ns. [Figure 6] This is to explain two types of spin-orbit interactions that exist in III-V semiconductor quantum well structures. Figure 6(a) shows the Rashba spin-orbit interaction, Figure 6(b) shows the Dresselhaus spin-orbit interaction, and Figure 6(c) shows the persistent spin orbit state. [Figure 7] FIG. 1 is an explanatory diagram illustrating the concept of electron spin waves. [Figure 8] 1 is an explanatory diagram showing an example of a circuit configuration that has an example of a III-V group semiconductor quantum well structure and is capable of multiplexing and transmitting electron spin waves. FIG. [Figure 9] 9 is a graph showing that a large effective magnetic field exceeding 10 T can be generated by controlling the gate voltage in the circuit configuration shown in FIG. 8. [Figure 10] FIG. 1 is an explanatory diagram showing an overview of superposition, transport, and separate detection of multiple electron spin waves. [Figure 11] FIG. 10 is an explanatory diagram showing the concept of providing a region where a gate can be applied midway through the transport of multiple electron spin waves. [Figure 12]1 is a schematic diagram showing a specific structure of a portion that performs gate control and an equivalent circuit of a set difference gate corresponding to the structure. [Figure 13] 1 is a schematic diagram showing the specific structure of the portion that performs spin injection and amplification and the equivalent circuit configuration of the collective generation gate corresponding to that structure. [Figure 14] 1 is a schematic diagram showing a specific structure used when superposing multiple electron spin waves by wiring coupling and an equivalent circuit of a set sum gate corresponding to the structure. [Figure 15] FIG. 1 is an explanatory diagram showing the concept of generating multiple electron spin waves using multiple polarized beams. [Figure 16] FIG. 10 is a perspective view showing an example of a structure for collectively photoelectrically converting multiple pieces of information. [Figure 17] The diagram shows a configuration for generating and amplifying electron spin waves by utilizing the magnon resonance excitation phenomenon through the input of multiple electron spin waves. Figure 17(a) is a schematic diagram of a device that injects spins by spin pumping, Figure 17(b) is a schematic diagram showing the configuration of an element that reverses magnetization by magnon resonance excitation, and Figure 17(c) is a schematic diagram for explaining magnons. [Figure 18] FIG. 1 is a schematic diagram showing a configuration for selectively writing and reading information from multiple electron spin waves. [Figure 19] FIG. 19 is a schematic diagram showing the write conditions for selectively electrically writing information by electron spin waves in the molecular configuration shown in FIG. [Figure 20] FIG. 10 is an explanatory diagram for explaining a method for recording information received from electron spin waves in multiple states. [Figure 21] 1 is a schematic diagram showing an electron spin wave multiplex transmission device according to an embodiment of the present invention; [Figure 22] FIG. 1 is an explanatory diagram showing a basic structure for confirming that spin injection, transport, and detection are possible in a stacked structure of a ferromagnetic metal and a semiconductor. [Figure 23] FIG. 1 is an explanatory diagram showing a basic structure for confirming that electron spin waves can be controlled by spin pumping in a layered structure of a ferromagnetic metal and a semiconductor. [Figure 24] FIG. 1 is an explanatory diagram showing a basic structure for confirming that the dynamic behavior of a ferromagnetic metal can be modulated by electron spin waves in a layered structure of a ferromagnetic metal and a semiconductor. [Figure 25] FIG. 1 is an explanatory diagram showing a basic structure for confirming that multi-state recording is possible for a ferromagnetic metal memory using electron spin waves in a stacked structure of a ferromagnetic metal and a semiconductor. [Figure 26] 10A and 10B are schematic diagrams showing the specific configuration for branching multiple electron spin waves, finding the set difference and set sum, and recording information in the electron spin wave multiplex transmission device according to the embodiment, where (a) is a schematic diagram of the branching section, (b) is a schematic diagram showing the configuration for finding the set difference, (c) is a schematic diagram showing the configuration for finding the set sum, and (d) is a schematic diagram of the configuration for recording information. [Figure 27] FIG. 27 is an equivalent circuit diagram corresponding to the structure for calculating the set difference and set sum in the device shown in FIG. 26. [Figure 28] FIG. 10 is a diagram showing the conditions of the external magnetic field and excitation frequency for selective writing in a recording section having a recording magnetic material. [Figure 29] 1 is a circuit diagram showing an example of an optical communication device including a digital signal processing circuit, a DA converter, an AD converter, a polarization multiplexing optical modulator, and a coherent receiver. [Figure 30] FIG. 30 is a configuration diagram showing an electron spin wave multiplex transmission device that can replace part of the circuit shown in FIG. 29. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the drawings used in the following description may show characteristic portions enlarged for convenience in order to make the characteristics easier to understand. First, the technique of superposing electron spin waves will be described. The wavelength of electron spin waves changes depending on the strength of the effective magnetic field resulting from the spin-orbit interaction that occurs in semiconductor quantum well structures. Since each unique wavelength corresponds one-to-one to the transmitted information, the inventors believed that it would be possible to distinguish information by examining the wavelength of the spin waves.

[0023] The inventors discovered that by using a gate structure formed on the semiconductor surface, it is possible to change the strength of the effective magnetic field by controlling the gate voltage, thereby generating spin waves of any wavelength. Furthermore, in two-dimensional electron gases in semiconductor quantum structures, the wavelength of spin waves varies depending on the in-plane crystal orientation. In the persistent spin gyration state, as shown in Figure 6(c), the effective magnetic field experienced by electrons moving in a specific crystal orientation can be made zero. Therefore, by restricting the direction of electron motion using a thin wire structure, for example, it is possible to change the wavelength of stably existing spin waves from a specific value to infinity (plane wave). This makes it possible to control the amplitude, phase, and polarization degrees of freedom of electron spin waves.

[0024] A typical material capable of generating electron spin waves is a III-V compound semiconductor quantum well structure, and a solid-state device having a stacked structure such as that shown in Table 1 below can be used. However, materials capable of generating similar electron spin waves can be realized in a variety of solid-state devices, including not only III-V semiconductors but also II-VI semiconductor quantum well structures, SrTiO3 / LaAlO3 quantum well structures, and SiGe quantum well structures. It should be noted that various crystal orientations are possible, more specifically, the crystal orientations described in D. Iizasa et al., Physical Review B, 101, (2020), 245417. For example, the stacked structure shown in Table 1 below can be adopted. In Table 1, the constituent materials and layer thickness (nm) of each layer are shown, and QW indicates a quantum well structure.

[0025] [Table 1]

[0026] As a solid-state device having a III-V compound semiconductor quantum well structure capable of generating electron spin waves, the layered structure shown in Table 2 below may be adopted. Table 2 shows the constituent materials and layer thickness (nm) of each layer.

[0027] [Table 2]

[0028] As shown in Fig. 2(a) on page 3 of the paper "Drift-Induced Enhancement of Cubic Dresselhaus Spin-Orbit Interaction in a Two-Dimensional Electron Gas" by Yoji Kunihashi et al., Physical Review Letter 119, 187703 (2017), it is explained that the wavelength of the electron spin wave changes depending on the drift velocity of the electron, that is, the energy of the electron. Based on this finding, it is possible to generate different spin wave wavelengths by exciting electron spins with different electronic energies with light. Specifically, it is possible to generate multiple spin waves by superimposing and exciting circularly polarized light of different wavelengths.

[0029] In a method other than the above, spin-polarized electrons can be generated in a semiconductor by using a ferromagnet / semiconductor junction and performing electrical spin injection from the ferromagnet to the semiconductor. In the above structure, the electron spin polarization and electron density can be changed depending on the applied bias voltage, so in principle, it is possible to generate the spatial distribution of electron spin polarization and electron density created by multiple electron spin waves in a semiconductor by changing the bias voltage of the electrical spin injection.

[0030] In the present application, a circuit configuration similar to the circuit shown in FIG. 1 of the above-mentioned document can be applied. FIG. 8 is a schematic diagram showing a circuit similar to the circuit shown in FIG. 1 of the same document. In this circuit, the vertical strip-shaped wiring 1A, the horizontal strip-shaped wiring 1B, and the integrated wiring joint 1 that joins them in a cross shape have the laminated structure shown in Table 1, and by creating a Hall bar structure, it is possible to apply an electric field in the x or y direction in Figure 8. In the circuit of FIG. 8, the width of each of the wirings 1A and 1B is formed to 250 μm. Both ends of the wirings 1A and 1B are connected to wirings 2a and 3a, which are connected to the power supply 2 and the power supply 3, respectively. These connection parts are ohmic contact parts, and are connected to the voltage V in the x direction shown in FIG. x , voltage in the y direction V y The voltages indicated by are applied.

[0031] Furthermore, a gate electrode 5 made of a Cr / Au thin film is deposited in the region indicated by the rectangular frame (region surrounded by a rectangular frame 300 μm in length and width) so as to include the intersection of the wiring connection portion 1, and a gate voltage (V g ) can be applied. In addition, the size of each part of the circuit can be made equivalent to the circuit diagram in Figure 1 of the same document. In the structure shown in Figure 8, by thinning the film thickness of the quantum well structure as shown in Table 1, we can consider the structure as one in which the movement of electrons is restricted from three dimensions to two, and can grasp the duration of the electron spin waves that appear here. The strength of the higher-order Dresselhaus magnetic field depends on the crystal orientation when confining it in two dimensions. From this circuit it is possible to draw a Monte Carlo simulation.

[0032] The Monte Carlo simulation was performed using the latest version (R2020b) of "Matlab," a calculation software made by Math Works. The time evolution of electron spins as they sense an effective magnetic field and undergo precession can be described by the Bloch equation. Therefore, after generating spin polarization at t = 0, the analysis was performed as follows using a method in which the position information and spin components of the electron spins are updated using equations consisting of the parameters listed in Table 3 below.

[0033] For example, in the circuit shown in Figure 8, the area surrounded by the dashed line is used as the gate structure, and the gate voltage (V g ) can be applied to this gate structure. g ) is applied to the area enclosed by the rectangular frame. g It is possible to form electron spin waves corresponding to the spin-orbit interaction generated by V. g By changing the value of , different electron spin waves can be generated, so V g By controlling the value of , any wavelength can be produced. In Figure 8, the x direction indicates the direction parallel to the

[0110] in the quantum well structure crystal, the y direction indicates the direction parallel to the

[0110] in the quantum well structure crystal, and the z direction indicates the direction parallel to the

[0001] in the quantum well structure crystal.

[0034] The overbars attached to the Miller indices written in brackets [ ] indicating the crystal orientations described above are written as underbars instead, since this format cannot be used in patent specifications. As mentioned above, the gate voltage (V g The technology for generating different electron spin waves by changing the value of θ (orbit interaction) is described in a paper previously published by the present inventors: Makoto Kohda, et al., "Enhancement of spin-orbit interaction and the effect of interface diffusion in quaternary InGaAsP / InGaAs heterostructures," Physical Review B 81, 115118 (2010).

[0035] For example, Figure 9 shows the relationship between gate voltage and effective magnetic field described in the above-mentioned literature, and shows that by precisely controlling the gate voltage, it is possible to apply an effective magnetic field exceeding 10 T (tesla). The results in Figure 9 show that InP substrates are 0.52 Al 0.48As layer (thickness 200 nm), InGaAsP layer (thickness 5 nm), In 0.8 Ga 0.2 As layer (thickness 10 nm), InGaAlAs layer (thickness 3 nm), In 0.52 Al 0.48 The results were obtained in a solid-state device with an As layer (25 nm thick).

[0036] Figure 1 shows the superposition of electron spin waves generated in different directions. Monte Carlo simulation was used to generate the electron spin waves, and the specific parameters are shown in Table 3 below. The upper figures in FIG. 1 are inverse spaces (wave number spaces) obtained by performing a two-dimensional Fourier transform on the lower figures in FIG. 1, and show wave numbers, which are the reciprocals of wavelengths. Figure 1(a) shows a first example of the spin distribution of up spins and down spins in real space, and Figure 1(b) shows the inverse space (wave number space) obtained by applying a two-dimensional Fourier transform to the state shown in Figure 1(a). Figure 1(a) shows three vertical rows of spin distributions distributed in the left-right direction. Of the three rows in the top-bottom direction, the central distribution indicates an area with a high proportion of up spin, while the top and bottom two distributions indicate areas with a high proportion of down spin.

[0037] Figure 1(c) shows a second example of the spin distribution of up spins and down spins in real space, and Figure 1(d) shows the reciprocal space (wave number space) obtained by applying a two-dimensional Fourier transform to the state shown in Figure 1(c). Figure 1(c) shows three horizontal rows of spin distributions distributed in the vertical direction. Of the three rows, the central distribution indicates an area with a high proportion of up spin, while the two distributions on the left and right indicate areas with a high proportion of down spin. As can be seen in Figures 1(a) and (c), the direction of the electron spin wave changes depending on the direction of the spin-orbit interaction. The two-dimensional Fourier transform is a program that can transform two-dimensional matrices using a fast Fourier transform algorithm. In principle, it is equivalent to performing a fast Fourier transform twice, in the x and y directions.

[0038] Figure 1(e) shows a third example of the spin distribution of up spins and down spins in real space, and Figure 1(f) shows the reciprocal space (wave number space) obtained by applying a two-dimensional Fourier transform to the state shown in Figure 1(e). In Figure 1(e), regions with a high proportion of upspin are distributed to the left and right of the region with a high proportion of upspin, four regions above and below it, and there are regions with a high proportion of upspin on the two sides above and below it.

[0039] If the wavelength of the electron spin wave is λ, a peak appears at the wave number q, with a magnitude of q = 2π / λ. Figure 1(e) is a superposition of the waveforms in Figures 1(a) and 1(c), and Figure 1(f), which is the Fourier transform of Figure 1(e), maintains the peak positions of Figures 1(b) and 1(d). This means that electron spin waves possess the same parallelism and multiplicity as ordinary waves. The results shown in Figure 1 show that when two types of electron spin waves are superimposed, they overlap while maintaining their respective wavelengths (wave numbers). This proves that electron spin waves, like light, possess parallelism and multiplicity, and can be superimposed without interfering with each other.

[0040] As shown in Figures 1(b), (d), and (e), if the spin distribution is understood in the reciprocal space (wave number space) after a two-dimensional Fourier transform, the spin distribution can be understood more clearly than when the spin distribution is understood in real space. Therefore, when two types of electron spin waves are superimposed, each electron spin wave can be superimposed while maintaining its own wavelength (wave number). It was found that when multiple electron spins are superimposed and transmitted, they can be transported without interfering with each other, and that the waves can be superimposed as electron spin waves. Therefore, electron spin waves can be transmitted in wavelength division multiplexing, just like light.

[0041] [Table 3]

[0042] In Table 3, α is the strength of the Rashba spin-orbit interaction, β1 is the strength of the Dresselhaus spin-orbit interaction (linear term), β3 is the strength of the Dresselhaus spin-orbit interaction (cubic term), Ds is the spin diffusion constant, Ns is the carrier density, g is the g-factor, Electrons is the number of electrons, μ is the electron mobility, and Eex is the external electric field. In all cases, no external magnetic field is applied. The simulation was performed assuming that electrons are scattered in random directions every 10 ps.

[0043] "Multiplexed Information Transmission and Separation Detection" Next, a method for transmitting the generated multiple electron spin waves and a method for separating and detecting them will be explained. The present inventors have found that electron spin waves can be transported while maintaining their waveform by appropriately using a drift electric field and an external magnetic field (S. Anghel, et al. "Spin-locked transport in a two-dimensional electron gas", Physical Review B 101, 155414 (2020)). Furthermore, it was found that by setting the strength of the spin-orbit interaction in a solid to a specific value, it is possible to stably maintain only spin waves with a specific wavelength calculated from that, while eliminating other wavelength components.

[0044] 2 to 4 show the time evolution when electron spin waves with different wavelengths are generated in solid-state devices with the same strength of spin-orbit interaction. In Figure 2, the state is stable and can maintain its shape for a long time because it has the same characteristic wavelength determined by the strength of the spin-orbit interaction. On the other hand, in Figure 3, the wavelength is different from the inherent wavelength determined by the strength of the spin-orbit interaction in the semiconductor, and so the shape is lost in a short time. Figure 4 compares the two, and shows that the stable spin wave shown in Figure 2, unlike the unstable spin wave shown in Figure 3, can maintain the electron spin wave in the Z direction for a certain period of time. This means that only the stable electron spin wave can be maintained and transmitted, while the unstable electron spin wave can be attenuated and eliminated. The semiconductors assumed in FIGS. 2 to 4 are semiconductors having the parameters determined in Table 3 above.

[0045] In Figure 2, electron spin waves with a wavelength equal to the intrinsic wavelength (λ0 = 9.0 μm) uniquely determined by the strength of the spin-orbit interaction in the solid are excited at time 0, while in Figure 3, electron spin waves with a different wavelength (λ = 4.5 μm) are excited at time 0. Figure 2 maintains its shape for a long time, but Figure 3 loses its shape due to the spin relaxation mechanism. From the above, it can be said that if the strength of the spin-orbit interaction can be freely controlled, it will be possible to select and extract only the information contained in electron spin waves of any wavelength. This means that a spin filter has been created that can retain and transmit only stable electron spin waves (spin waves with a wavelength of λ0 = 9.0 μm) and attenuate and eliminate unstable electron spin waves (spin waves with a wavelength of λ = 4.5 μm).

[0046] In a semiconductor quantum well structure, the strength of the Rashba spin-orbit interaction and the Dresselhaus spin-orbit interaction is uniquely determined by the structure, such as the quantum well width. Because the wavelength of an electron spin wave is inversely proportional to the sum of the strengths of these two types of spin-orbit interactions, once a quantum structure is determined, the wavelength of the electron spin wave specific to the material that makes up that structure is uniquely determined. In this study, in semiconductors with spin-orbit interactions of the strengths listed in Table 3, electron spin waves with a wavelength of λ0 = 9.0 μm exist most stably.

[0047] As an example, Figure 5 shows a calculation example that demonstrates that using this principle, a state in which three electron spin waves are superimposed can be generated and transported by a drift electric field, thereby extracting only stable spins. The strength of the spin-orbit interaction is determined so that only electron spin waves with a specific wavelength are stable, and three waves are generated, including the stable electron spin wave. Specifically, Figure 5 shows the results of tracking the time evolution of electron spin waves excited with three wavelength components, λ1=20 μm, λ2=6.7 μm, and λ3=3.3 μm, while transporting them in the +Y direction.

[0048] As described in the previous section, the wavelength (λ) of electron spin waves is inversely proportional to the strength of the spin-orbit interaction. Therefore, by controlling the gate voltage or other factors, it is possible to control the strength of the spin-orbit interaction in the material and select the wavelength of the electron spin waves that exist most stably. The electron spin wave with three wavelength components was created in a Monte Carlo simulation by inputting the z-component (Sz) of the electron spin, which spreads according to a Gaussian distribution at t = 0, into the following formula as a function of position. A specific function is expressed as Sz(X)=cos(2π×0.05×X)+1.5cos(2π×0.15×X)+0.7cos(2π×0.3×X) (X: position [μm]).

[0049] Figures 5(d) and (e) assume a semiconductor with a spin-orbit interaction strength that stabilizes the wavelength of λ2, while Figures 5(f) and (g) assume a semiconductor with a spin-orbit interaction strength that stabilizes the wavelength of λ3. Figures 5(b) and (c) show the real-space and reciprocal-space distributions of multiple spin waves with three wavelength components, λ1 = 20 μm, λ2 = 6.7 μm, and λ3 = 3.3 μm, and Figure 5(a) shows the cross section at Y = 0 in Figure 5(b). Figures 5(d) and (e) show the results when this multi-wave is injected into a region where λ2 is stable and allowed to drift in the +Y direction for 1 ns, while Figures 5(f) and (g) show the results when injected into a region where λ3 is stable.

[0050] In these figures, it can be seen that the electron spin waves are changing their shape as they move in the +Y direction as a whole. At this time, components other than the stable wavelengths disappear over time, making it possible to extract only specific wavelength components from the multiplexed electron spin waves. This shows that it is possible to transport electron spin waves of different wavelengths in a superimposed manner, while simultaneously extracting specific wavelength components. In other words, by locally modulating the strength of the spin-orbit interaction at a specific location using an electron spin wave filter, it is possible to freely change the waveform of the electron spin wave passing through that location by drift transport.

[0051] In the above explanation, the strength of the spin-orbit interaction at a specific point is determined by, for example, the gate voltage (V g ) is proportional to V g The strength of the spin-orbit interaction can be determined from the value of . Also, local modulation means that only the gate electrode formation region in the circuit of Figure 8 is modulated, and the region where the gate electrode is not formed is not modulated. Also, passing by drift transport means that in the circuit of Figure 8, the gate voltage (V x ) can be applied to move electrons from the left to the right of the circuit by the electric field. This is the drift transport, which is explained as passing from the region where the gate electrode 5 is not formed through the region where the gate electrode 5 is formed and then back into the region on the opposite side where the gate electrode is not formed.

[0052] From the above explanation, it has been demonstrated that by utilizing the permanent spin rotation state in the crystal orientation dependence of the effective magnetic field due to spin-orbit interaction that occurs in a semiconductor quantum well structure and controlling the amplitude, phase, and polarization degrees of freedom of the electron spin wave, it is possible to superimpose multiple electron spin waves, and furthermore, it has been demonstrated that multiple electron spin waves can be transmitted in a solid-state device having the semiconductor quantum well structure. Furthermore, in a solid-state device having a semiconductor quantum well structure (the circuit described above), by transmitting electron spin waves of a wavelength equal to a specific wavelength determined uniquely from the strength of the spin-orbit interaction and eliminating electron spin waves of wavelengths different from the specific wavelength determined uniquely from the strength of the spin-orbit interaction, it was demonstrated that only electron spin waves of a specific wavelength can be transmitted in a solid-state device.

[0053] Furthermore, when there are a large number of electron spin waves, by converting the data obtained by real-space measurements into wavenumber space data through fast Fourier transform and analyzing it, it was found that it is easy to confirm how the spin waves change shape as they move. In this case, components other than the stable wavelengths disappear over time, so it was also proven that it is possible to extract only specific wavelength components from the multiple waves.

[0054] From the above explanation, it has been found that it is possible to superimpose two or more types of electron spin waves, maintain the unique wavelength of each electron spin wave, and transmit the superimposed waves through the above-mentioned transmission line without interfering with each other. Therefore, using the above-mentioned multiple electron spin waves, it is possible to achieve transmission similar to wavelength division multiplexing transmission in the optical field, and if the transmitted multiple electron spin waves are separated into the electron spin waves before multiplexing and the information contained in each electron spin wave is detected, it is thought that the conventional optical wavelength division multiplexing transmission technology can be partially replaced by the use of multiple electron spin waves.

[0055] The information transmission technology, information recording technology, and information separation and analysis technology using multiple electron spin waves will be described in more detail below. FIG. 10 is an explanatory diagram showing the concept of superimposing electron spin waves to synthesize multiple electron spin waves, transmitting the synthesized multiple electron spin waves, recording information on the multiple electron spin waves after transmission, and reading out this information. FIG. 11 is an explanatory diagram showing the concept of superimposing electron spin waves to synthesize multiple electron spin waves, transmitting the synthesized multiple electron spin waves along a transmission path R1 consisting of the above-mentioned solid-state device, and modulating and drift-transporting the multiple electron spin waves using a gate electrode 10 provided midway along the transmission path R1.

[0056] As explained above, if gate control can be performed midway along transmission line R1 by using the gate structure shown in Fig. 12, for example, it can be used as an arithmetic element using a collective difference gate shown in the equivalent circuit on the right side of Fig. 12. The gate structure shown in Fig. 12 is a structure in which gate electrode 10 is stacked on transmission line R1 for multiple electron spin waves, as shown in Figs. 8, 11, etc. Furthermore, if a solid-state device capable of spin injection and amplification as shown in FIG. 13 can be realized, it can be used as an arithmetic element using a collective generation gate as shown in the equivalent circuit on the right side of FIG. Furthermore, if a solid-state device in which the wires shown in FIG. 14 are connected in a cross shape can be realized, it can be used as an arithmetic element using a set sum gate as shown in the equivalent circuit on the right side of FIG. The solid-state device shown in FIG. 14 in which wires are coupled in a cross shape can employ a structure equivalent to the wire coupling portion 1 shown in FIG. 8 in which wires 1A and 1B are coupled in a cross shape. If we have the necessary arithmetic elements that can perform operations using these three basic logic types, such as the set difference gate, set generation gate, and set sum gate, we can build a parallel arithmetic function that can perform general-purpose parallel calculations. The structure of each solid-state device shown in Figures 13 and 14 will be described in detail later.

[0057] A specific configuration for realizing multiplexed information transmission function of optical communication and semiconductor using multiple electron spin waves will be further described below. Figure 15 shows the concept of a single polarized beam used in current optical communication technology. Until now, optical information transmission in optical communication technology has been carried out using a single polarized beam. However, in this embodiment, multiplexed polarized beams are superimposed on an optical signal. Each piece of optical polarization information can generate a separate electron spin wave. By using multiply polarized beams based on this principle, it is possible to directly generate multiple electron spin waves in solid-state devices made of semiconductors. For example, based on the optical transition selection rules, it is possible to transfer information multiplexed in the optical signal mentioned above to electron spin waves. This makes it possible to simultaneously convert multiple information into electrical signals.

[0058] FIG. 16 shows an example of a configuration that can realize simultaneous photoelectric conversion of information from multiple polarized beams. 16, reference numeral 12 denotes an injection portion including a portion of the transmission line R1 having the above-described quantum well structure, and reference numeral 13 denotes a rectangular ferromagnetic layer made of a ferromagnetic metal layer. The ferromagnetic layer 13 is made of a ferromagnetic metal layer such as a Py (NiFe alloy) layer, a CoFeB layer, or a Heusler alloy layer. The ferromagnetic layer 13 is formed on the injection portion 12 so as to cross the injection portion 12 from one end to the other end in the width direction of the injection portion 12. In the above-described configuration, the injection portion 12 is irradiated with a multi-polarized beam, and the ferromagnetic layer 13 is energized to control the electron spin wave by spin pumping, which will be described later. The structure for generating electron spin waves uses the principle of optical transition selection, which can transfer the angular momentum of light to the angular momentum of spin by irradiating the multiply polarized beam shown in Fig. 15 using, for example, the semiconductor quantum structure shown in Table 1. By directly transferring the polarization information consisting of the angular momentum of light contained in the multiply polarized light to the angular momentum of electron spin in the semiconductor quantum structure, i.e., electron spin waves, it is possible to generate electron spin waves at the introduction part 12 using the multiply polarized beam.

[0059] In the information processing using multiple electron spin waves of this embodiment, electron spin waves generated by the spatial rotation of electron spins are utilized as wave-like information carriers in solid-state devices. The method for controlling the multiplexed electron spin waves can be implemented as described below. The effective magnetic field generated by spin-orbit interactions in solid-state devices can rotate electron spins in the time and space domains. In particular, electron spin waves can be stabilized under a special condition called the persistent spin orbit state. As mentioned above, this state can be controlled externally by applying a voltage to the gate structure of the solid-state device. By applying a gate voltage to the gate electrode, the wavelength of the stabilized electron spin waves can be arbitrarily controlled.

[0060] Therefore, when multiplexed electron spin waves are drift-transported to a region where a gate voltage is applied, only the multiplexed electron spin waves that can be most stabilized by the applied gate voltage survive, and electron spin waves with other wavelengths can be erased. The fact that this principle can be used to electrically separate any electron spin waves was previously explained using Figure 8, and the concept of constructing a collective difference gate by controlling the gate voltage is shown in Figure 12.

[0061] Next, a stacked structure of ferromagnetic material and transmission line can be used to configure a solid-state device capable of spin injection and amplification, as shown in Fig. 13. As an example, in Fig. 13, a solid-state device capable of spin injection and amplification can be configured by providing a rectangular first ferromagnetic material layer 13 and a second ferromagnetic material layer 14 in the middle of transmission line R1. Ferromagnetic resonance in a ferromagnetic material can induce precession in the magnetization of the ferromagnetic material. When precession is occurring, if a current is passed from the ferromagnetic material to the transmission line R1, electron spins that follow the magnetization direction are injected into the transmission line R1. This makes it possible to inject electron spin waves that depend on the ferromagnetic resonance frequency into the transmission line using electric current. By temporally controlling the voltage applied between the laminated structure of the ferromagnetic material and the transmission line, electron spin waves with any wavelength can be injected into the transmission line R1, making it possible to electrically generate multiple electron spin waves.

[0062] Furthermore, by using the reverse principle of the above, electron spin waves can be detected using ferromagnetic materials. Specifically, magnetization dynamics or magnons with the same frequency as the electron spin waves are induced in the ferromagnetic material by magnetic resonance. When the ferromagnetic resonance frequency of the electron spin waves and the ferromagnetic material matches, the electron spin waves can receive spin angular momentum, increasing the amplitude of the ferromagnetically resonating magnetization. On the other hand, if the frequency deviates from the resonance condition, nothing happens. This principle allows electron spin waves to be detected as changes in the linewidth and amplitude intensity of ferromagnetic resonance. By using the various principles explained above, it is possible to realize information processing using a wave information device using the structures shown in Figures 12 to 14. Specifically, it is possible to realize three different gate operations as shown in the equivalent circuits on the right side of Figures 12, 13, and 14, which make it possible to configure a general-purpose parallel computer. This means that parallel computing functions can be constructed using electron spin waves.

[0063] Information recording using electron spin waves will be described in detail below. For information recording, a laminated structure of a ferromagnetic material and a transmission line shown in FIG. 17 can be used. 17(a), in a transmission line R2 formed by a nonmagnetic semiconductor 15, a first ferromagnetic layer 16 and a second ferromagnetic layer 17 in the shape of strips are formed at a predetermined interval on the transmission line R2 along the direction of transport of electron spin waves. The nonmagnetic semiconductor 15 is a semiconductor as a solid-state device having a III-V compound semiconductor quantum well structure on a substrate, and functions as the transmission line R2 that transports electron spin waves as in the example described above.

[0064] The length directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 17 are oriented perpendicular to the propagation direction RD of the electron spin wave. 17(b), the ferromagnetic layer 17 has a laminated structure of an upper magnetic layer (recording magnetic layer) 20 and a lower magnetic layer (base magnetic layer) 21, where the upper magnetic layer 20 is a layer that records information and the lower magnetic layer 21 is a layer that excites magnons, which will be described later. The upper magnetic layer 20 is made of, for example, an FePt layer, and the lower magnetic layer 21 is made of, for example, a ferromagnetic metal layer such as a Py (NiFe alloy) layer, a CoFeB layer, or a Heusler alloy layer.

[0065] Magnons can be excited in the ferromagnetic material by transferring the spin angular momentum of electron spins from the multiple electron spin waves propagating through the nonmagnetic semiconductor 15 to the ferromagnetic material of the first ferromagnetic layer 16. As shown in Figure 17(c), magnons are waves with continuous changes in magnetic order, and their magnetization is fixed. In contrast, electron spin waves are waves in which electron spins rotate around the effective magnetic field, as explained above with reference to Figure 7.

[0066] The upper magnetic layer 20 is magnetically coupled to the lower magnetic layer 21, and when magnons and spin waves are excited in the lower magnetic layer 21 due to resonant excitation of magnons by electron spin waves, the magnetization of the upper magnetic layer 20 is also reversed accordingly. Since magnons can be excited only when they have the same resonant frequency as the electron spin wave, it is possible to selectively write information to the upper magnetic layer 20 depending on the wavelength of the electron spin wave. Specifically, as an example, the magnetization state is shown by multiple arrows in Figure 17(b).

[0067] Taking the above-mentioned state into consideration, more specifically, a structure can be adopted in which three ferromagnetic materials, a first recording magnetic material 27, a second recording magnetic material 28, and a third recording magnetic material 29, are formed on a semiconductor solid-state device 22 that is shaped like a cross in a plan view, as shown in Fig. 18. The semiconductor solid-state device 22 has, as an example, a structure equivalent to the wiring coupling portion 1 shown in Fig. 8, based on the stacked structure shown in Table 1 above.

[0068] The first recording magnetic body 27 is a layer formed by laminating an upper magnetic layer (recording magnetic layer) 27b for recording information and a lower magnetic layer (base magnetic layer) 27a having a magnon resonance frequency. The second recording magnetic body 28 is a layer formed by stacking an upper magnetic layer (recording magnetic layer) 28b for information recording and a lower magnetic layer (base magnetic layer) 28a having a magnon resonance frequency, and the third recording magnetic body 29 is a layer formed by stacking an upper magnetic layer (recording magnetic layer) 29b for information recording and a lower magnetic layer (base magnetic layer) 29a having a magnon resonance frequency. In the structure of Figure 18, when multiple electron spin waves with different electron spin wave wavelengths (i.e., frequencies) reach the first recording magnetic body 27, the second recording magnetic body 28, and the third recording magnetic body 29, the ferromagnetic body that can resonate with them varies depending on the wavelength = frequency of the electron spin waves.

[0069] For example, the first electron spin wave indicated by reference numeral 31 in FIG. 18 can excite magnons only in the lower magnetic layer 27a of the first recording magnetic body 27, causing the upper magnetic layer 27b to reverse its magnetization and change its magnetization state. The second electron spin wave indicated by reference numeral 32 in FIG. 18 can excite magnons only in the lower magnetic layer 28a of the second recording magnetic body 28, causing the upper magnetic layer 28b to reverse its magnetization and change its magnetization state. The third electron spin wave indicated by reference numeral 33 in FIG. 18 can excite magnons only in the lower magnetic layer 29a of the third recording magnetic body 29, causing the upper magnetic layer 29b to reverse its magnetization and change its magnetization state.

[0070] In this way, by selectively exciting only the magnons of the ferromagnetic material that have the same resonant frequencies as the three types of electron spin waves, it is possible to nonvolatilely record the information of the multiple electron spin waves as multiple states in the first recording magnetic material 27, the second recording magnetic material 28, and the third recording magnetic material 29. Using this principle, it is possible to electrically detect the information contained in the multiple electron spin waves. In each of the recording magnetic materials 27, 28, and 29, information can be recorded on the upper magnetic layer side by magnons excited on the lower magnetic layer side, based on the same principle as in the example described with reference to FIGS. 17(a) and 17(b). In the explanation based on Figures 17 and 18, only a configuration having a magnetic layer with magnetization oriented in the film plane was mentioned, but a combination structure of a perpendicular magnetization film with magnetization oriented perpendicular to the film plane and a magnetic vortex can also be used to record and read the above-mentioned information. As the perpendicular magnetization film, for example, films such as (Fe-Pt alloy, Fe-Pd alloy, Mn-based alloy, Co / Pt multilayer film, Co / Pd multilayer film, Co / Ni multilayer film) can be used, and as the magnetic vortex, for example, structures such as (Co-Fe alloy, Ni-Fe alloy, Co-Mn-Si alloy, Co-Fe-Al alloy, Co-Fe-Si alloy) can be used.

[0071] 17 and 18, magnons are excited in the lower magnetic layer and the magnetization state is recorded in the upper magnetic layer. However, if the configurations shown in Figures 17 and 18 are inverted, magnons may be resonantly excited in the upper magnetic layer and the magnetization state may be recorded in the lower magnetic layer. In this case, the upper magnetic layer is used as the base magnetic layer, and the lower magnetic layer is used as the recording magnetic layer. For example, if transmission line R2 is disposed on the underside of nonmagnetic semiconductor 15, an upper magnetic layer is formed in contact with the underside of nonmagnetic semiconductor 15, and a lower magnetic layer is formed below that. In this case, electron spin waves in transmission line R2 excite magnons on the upper magnetic layer side and record the magnetization state on the lower magnetic layer side. In the configuration of this embodiment, a base magnetic layer capable of magnon resonance excitation is disposed on the side in contact with transmission line R2, and a recording magnetic layer capable of magnetization reversal is provided so as to connect to the base magnetic layer. The configurations shown in Figures 17 and 18 are examples of the arrangement of each magnetic layer, and as mentioned above, they may be turned upside down, and there are no particular restrictions on the arrangement direction etc. of the nonmagnetic semiconductor 15 and transmission line R2.

[0072] Figure 19 is a graph showing the magnetic field and frequency conditions for magnetization reversal in the first recording magnetic material (Element 1) 27, the second recording magnetic material (Element 2) 28, and the third recording magnetic material (Element 3) 29, with the frequency of the electron spin wave on the horizontal axis and the magnetic field on the vertical axis. As an example, the first recording magnetic material (Element 1) 27 is a recording magnetic material having an oblong shape in a planar view with a major axis of approximately 1 μm and a minor axis of approximately 500 nm, the second recording magnetic material (Element 2) 28 is a recording magnetic material having an oblong shape in a planar view with a major axis of approximately 500 nm and a minor axis of approximately 250 nm, and the third recording magnetic material (Element 3) 29 is a recording magnetic material having an oblong shape in a planar view with a major axis of approximately 250 nm and a minor axis of approximately 125 nm. From the relationship shown in FIG. 19, assuming that the magnetic characteristics (spin wave frequency) of each magnetic layer are known, it is possible to determine in which recording magnetic material information is recorded, from the value of the DC component Hdc of the magnetic field.

[0073] The above-mentioned nonvolatile multi-state recording method will now be described in detail. Table 4 below shows combinations to illustrate the multi-state non-volatile recording method.

[0074] [Table 4]

[0075] As shown in Table 4 and Figure 20, ferromagnetic materials are prepared with different resonance frequencies f1, f2, and f3 corresponding to the wavelengths of the electron spin waves. For example, these refer to the ferromagnetic materials of the first recording magnetic material 27, second recording magnetic material 28, and third recording magnetic material 29 shown in Figure 18. Only when the frequency of the electron spin and the ferromagnetic resonance frequency of the magnetization are magnons excited, as in the case shown in Figure 17(b), will magnetization reversal occur in the upper magnetic layer of each recording magnetic material. In the example shown in Table 4 and FIG. 20, for example, the resonance frequency fr of the first recording magnetic material 27 is f1, V PHE = ±4V, the resonance frequency fr of the second recording magnetic material 28 = f2, V PHE = ±2V, the resonance frequency fr of the third recording magnetic material 29 = f3, V PHE = ±1V, where the output V PHE can be controlled by the size of the element, taking advantage of the fact that the larger the element, the greater the resistance change due to the planar Hall effect. When three types of electron spin waves are multiplexed, it is possible to realize 2 to the power of 3, or eight different multiplexed states. To record these eight different pieces of information, a three-row arrangement of recording magnetic material is fabricated. Depending on the type and presence or absence of electron spin waves, it is possible to record eight different states, as shown in Table 4. This allows multiple information of multiple electron spin waves to be recorded as multi-state nonvolatile magnetic recording.

[0076] FIG. 21 is a diagram showing an example of a wave-based information device (electron spin wave multiplex transmission device) configured using the structure that enables information processing, information transmission, and information recording using electron spin waves as described above. The wave information device (electron spin wave multiplex transmission device) 40 of this example comprises an introduction section 41, a modulation section 42, and a recording section 43. The introduction section 41, the modulation section 42, and the recording section 43 are connected by the transmission path R1 described in detail above. The introduction section (multiple photoelectric conversion section) 41 has a structure equivalent to that shown in FIG. 16, and has a function of directly generating multiple electron spin waves in a semiconductor by multiple photoelectric conversion using multiple polarized light.

[0077] When the modulator section 42 adopts a structure having the gate electrode 10 described above with reference to Figures 11 and 12, it functions as a collective difference gate that gates the multiple electron spin waves transmitted through the semiconductor solid-state device. When the structure shown in FIG. 13 is adopted, the modulation section 42 functions as a collective generation gate capable of spin injection and amplification. When the modulation section 42 employs the structure shown in FIG. 14, it functions as a sum-of-signals gate.

[0078] 11 to 14 can be formed in one or more of the transmission lines R1 of the multiple electron spin waves. The transmission lines R1 formed in the introduction section 41, modulation section 42, and recording section 43 are all transmission lines formed as solid-state devices in which the semiconductor quantum well structures shown in Table 1 and the like described above are formed on a substrate. In the wave information device (electron spin wave multiplex transmission device) 40, for convenience, the transmission line R1 formed in the introduction section 41 can be referred to as the transmission line formed in the first solid-state device D1. Similarly, the transmission line R1 formed in the modulation section 42 can be referred to as the transmission line formed in the second solid-state device D2, and the transmission line R1 formed in the recording section 43 can be referred to as the transmission line formed in the third solid-state device D3.

[0079] 21, a plurality of first recording magnetic bodies 27, a plurality of second recording magnetic bodies 28, and a plurality of third recording magnetic bodies 29 are arranged lengthwise and widthwise in the surface direction on a solid-state device D3 of a recording unit 43. When a plurality of first recording magnetic bodies 27, second recording magnetic bodies 28, and third recording magnetic bodies 29 are arranged in the recording unit 43, a total of approximately 10 to 100 of them can be provided, as shown in the example described later with reference to FIG. 26(d). When the first recording magnetic body 27, the second recording magnetic body 28, and the third recording magnetic body 29 are provided, 3 It has been explained above that recording of 8 states can be realized, and by providing several tens to several hundreds of such states in the recording section 43 as described above, it becomes possible to record information.

[0080] 21, information multiplexed by polarization in optical communication is converted into a multiple electron spin wave collectively by an introduction section 41. The multiple electron spin wave is then transmitted through a transmission line R1 made of a solid-state device having a semiconductor quantum well structure such as InGaAs / InAlAs, and the spin-orbit interaction of the multiple electron spin wave is controlled by a gate electrode 10 provided in a modulation section 42, thereby realizing information processing as a collective difference gate using the multiple electron spin wave. Finally, the multiplexed information contained in the processed multiple electron spin waves can be nonvolatilely recorded as multiple states as described above using a recording unit 43 in which multiple ferromagnetic materials are arranged. This makes it possible to build a system that can manipulate multiple information using the wave information device 40 in all of information communication, information processing, and information recording.

[0081] Next, the principle of spin injection, transport of electron spin waves, and detection of electron spin waves using the above-mentioned stacked structure of ferromagnetic metal and transmission line will be described. FIG. 22 shows an example in which a first ferromagnetic layer 16 and a second ferromagnetic layer 17 made of thin films each having an elongated rectangular shape in plan view are formed on the upper surface of the nonmagnetic semiconductor 15 shown in FIG. 17(a). By causing ferromagnetic resonance in a ferromagnetic material, it is possible to cause the magnetization to precess over time. This precession of magnetization changes the magnetization direction over time, and for example, upward and downward magnetization components perpendicular to the surface are generated in a ferromagnetic thin film. These magnetization components rotate over time. When a bias current is applied to this rotational motion to cause electrons to flow from the first ferromagnetic layer 16 to the non-magnetic semiconductor 15, the electrons can be injected while changing between upward and downward spins over time, forming electron spin waves. This is the electrical injection of electron spin waves.

[0082] As explained in the previous example, the electron spin wave is drift-transported by the bias voltage applied from the gate electrode, and when the detection recording magnetic material has a ferromagnetic resonance frequency that is the same as the wavelength of the electron spin wave, i.e., the precession frequency, the spin angular momentum can be transferred to the ferromagnetic material by mutual conversion of spin angular momentum (i.e., by spin transfer torque), and the linewidth and amplitude of the ferromagnetic resonance change. This can be electrically detected in the second ferromagnetic layer 17, thereby enabling electrical detection of the electron spin wave. Figure 24 shows the change in the linewidth of the ferromagnetic resonance. As shown in Figure 24, the linewidth can be modulated, which indicates that spin angular momentum can be transferred from the electron spin wave to the second ferromagnetic layer 17, thereby modulating the magnetization dynamics.

[0083] FIG. 23 is a structural diagram illustrating the principle by which electron spin waves can be controlled by spin pumping in a configuration having a first ferromagnetic layer 16 and a second ferromagnetic layer 17 on the upper surface of the nonmagnetic semiconductor 15 shown in FIG. 17(a). 23, when electron spin waves are transported along transmission line R2, light is irradiated onto the top surface of nonmagnetic semiconductor 15. With this configuration, it becomes possible to detect modulation of electron spin waves by an optical method in parallel with an electrical method. 25 shows an example of a case where the spin angular momentum transferred from the electron spin wave increases and magnetization is reversed in a configuration in which the first ferromagnetic layer 16 and the second ferromagnetic layer 17 are provided on the upper surface of the nonmagnetic semiconductor 15 shown in FIG. 17(a). The condition for ferromagnetic resonance to occur is that only a ferromagnetic material has the same frequency as the electron spin wave, so it is clear that electron spin wave information can be selectively recorded only in a specific ferromagnetic material.

[0084] FIG. 26 shows a modification of the wave information device 40 shown in FIG. In the wave information device 40 shown in Figure 21, the transmission path R1 consisting of a solid-state device formed in the introduction section 41 can be divided into three thin transmission paths R3, R4, and R5 as shown in Figure 26(a), and can be configured so that multiple electron spin waves can be transmitted along each of the three transmission paths R3, R4, and R5. 26(b), a gate electrode 10 is provided for each transmission line, and by controlling the gate, each of the transmission lines R4 and R5 can be made to function as a set difference gate. Also, by combining the branched transmission lines R3 and R4 at the terminal ends of the transmission lines R3 and R4 as shown in FIG. 26(c), a set sum gate can be configured. The structure in which two set difference gates are connected to one set sum gate as shown in FIGS. 26(b) and 26(c) can be represented by an equivalent circuit shown in FIG.

[0085] After branching as described above, at the end of the integrated transmission line, a semiconductor solid-state device 22 having a cross shape in plan view, which has the structure explained above based on Fig. 18, is formed as shown in Fig. 26(d). Furthermore, several hundred recording magnetic materials are formed on the semiconductor solid-state device 22 in the vertical and horizontal directions on the top surface of the solid-state device 22. Figure 26(d) shows a recording magnetic material with a laminated structure of Co2MnSi layers and FeCo layers, in which a large number of recording magnetic materials are formed, each having the same structure as the first recording magnetic material 27, the second recording magnetic material 28, and the third recording magnetic material 29 previously explained with reference to Figure 18. The example of Figure 26(d) shows a state in which about 400 recording magnetic materials are formed in an area of ​​approximately 15 μm × 15 μm in a semiconductor solid-state device 22 that is cross-shaped in plan view. The structures shown in Figures 26(a), (c), and (d) can all be manufactured using current semiconductor microfabrication technology, and therefore the structures shown in Figures 21 and 26 are structures that can be realized on a substrate as solid-state devices.

[0086] Figure 28 is an explanatory diagram that assumes a case in which, in a structure in which multiple recording magnetic materials are arranged vertically and horizontally, the magnetization of each recording magnetic material is reversed by the spin transfer effect from electron spin waves, and resonant switching by spin pumping is possible. As shown in FIG. 28, selective writing is believed to be possible by adjusting the resonance frequency of the recording magnetic material to be written to.

[0087] FIG. 29 is a diagram showing an example of a configuration of a high-speed optical transmission system for next-generation optical communications. In Figure 29, reference numeral 50 denotes a digital signal processing circuit, 51 denotes a digital-to-analog converter (DAC), 52 denotes an analog multiplexer, 53 denotes a polarization multiplexed IQ (In-phase quadrature) optical modulator, 54 denotes a coherent receiver, and 54 denotes an analog-to-digital converter (ADC). An optical signal (laser) as an analog signal is input to a coherent receiver 54 from an input transmission fiber 56 , and the signal converted into a digital signal by an analog-to-digital converter 55 is processed by a digital signal processing circuit 50 . The digital signal processed by the digital signal processing circuit 50 is converted into an analog signal by a digital-to-analog converter 51, and an optically modulated signal is generated by a polarization multiplexed IQ optical modulator 53 and transmitted through an output transmission fiber 57.

[0088] The polarization multiplexed IQ optical modulator 53 and the analog multiplexer 52 constitute, for example, an integrated module 59 . Furthermore, it is desirable to integrate the structure from the coherent receiver 54 to the analog-to-digital converter 55 into a module, and the wave information device (electron spin wave multiplexing transmission device) 40 shown in FIG. 21 can be applied to the above-mentioned structure as the configuration shown in FIG. 30.

[0089] Multiple polarized light from the input transmission fiber 56 is introduced into the introduction section 41 to generate multiple electron spin waves, which can be transmitted along the transmission path R1 without wavelength separation. Furthermore, the information contained in the multiple electron spin waves can be recorded in the first to third recording magnetic materials 27, 28, and 29 of the recording unit 43. Analog-to-digital conversion is performed by reading out the information recorded in the first to third recording magnetic materials 27, 28, and 29 as the digital signals shown in Table 4 above. By sending these digital signals to the digital signal processing circuit 50, the structure from the coherent receiver 54 to the analog-to-digital converter 55 shown in Fig. 30 can be replaced. The entire structure of the wave information device (multiple electron spin wave transmission device) 40 shown in FIGS. 21 and 30 is 10 μm in size according to current general semiconductor miniaturization technology. 2 Since the optical transmission system can be formed in a range of about 1 / 2 mm, the above-mentioned optical transmission system can be miniaturized and realized. [Explanation of symbols]

[0090] 1... Wiring connection part, 1A, 1B... Wiring, 2, 3... Power supply, 2a, 3a... Wiring, 5... Gate electrode layer, 6... Power supply, V g : Gate voltage, V x : voltage applied in the x direction, V y: Voltage applied in the y direction, 10... gate electrode, 13, 14... ferromagnetic layer, 15... non-magnetic semiconductor, 16... first ferromagnetic layer, 17... second ferromagnetic layer, 20... upper magnetic layer (recording magnetic layer), 21... lower magnetic layer (base magnetic layer), 27... first recording magnetic material, 27a... lower magnetic layer (base magnetic layer), 27b... upper magnetic layer (recording magnetic layer), 28... second recording magnetic material, 28a... lower magnetic layer (base magnetic layer), 28b... upper magnetic layer (recording magnetic layer), 29... third recording magnetic material, 29a... lower magnetic layer (base magnetic layer), 29b... upper magnetic layer, 40... multiplexed transmission device (wave information device), 41... introduction section, 42... modulation section, 43... recording section, D1... first solid-state device, D2... second solid-state device, D3... third solid-state device.

Claims

1. an introduction unit having a first solid-state device having a semiconductor quantum well structure, which synthesizes a plurality of electron spin waves to introduce a multiple electron spin wave; a modulation section having a second solid-state device having a semiconductor quantum well structure connected to the introduction section, the modulation section modulating the multiple electron spin waves from the introduction section; a third solid-state device having a semiconductor quantum well structure connected to the modulation section, the multiple electron spin waves having passed through the modulation section being introduced thereinto, and a recording section having a plurality of recording magnetic bodies for nonvolatilely recording information contained in the multiple electron spin waves; An electron spin wave multiplex transmission device characterized in that the modulation unit is a modulation unit that has the function of controlling at least one of the amplitude, phase, and polarization degrees of freedom of the electron spin wave by utilizing the permanent spin rotation state in the crystal orientation dependence of the effective magnetic field due to spin-orbit interaction that occurs in a semiconductor quantum well structure.

2. 2. The electron spin wave multiplexing transmission device according to claim 1, characterized in that in the solid-state device having the semiconductor quantum well structure, electron spin waves of a wavelength equal to a specific wavelength uniquely determined by the strength of the spin-orbit interaction are transmitted, and electron spin waves of a wavelength different from the specific wavelength uniquely determined by the strength of the spin-orbit interaction are eliminated, thereby having the function of transmitting only electron spin waves of a specific wavelength in the solid-state device.

3. An electron spin wave multiplex transmission device as described in claim 1 or claim 2, characterized in that when the number of electron spin waves is large, the device is provided with a function to perform a fast Fourier transform on the data obtained by real space measurement to convert it into wave number space data and analyze it.

4. An electron spin wave multiplex transmission device as described in claim 1 or claim 2, characterized in that the modulation section is provided with one or more of a gate electrode for applying voltage, a ferromagnetic layer for spin injection and amplification, and a wiring coupling section for coupling the electron spin waves.

5. 3. An electron spin wave multiplex transmission device as described in claim 1 or claim 2, characterized in that a plurality of the recording magnetic bodies, each having a base magnetic layer and a recording magnetic layer, are arranged in the recording section, the base magnetic layer is a magnetization reversal layer that excites magnons by the electron spin waves and resonates with the excitation of the magnons to reverse its magnetization, the recording magnetic layer reverses its magnetization in response to the magnetization reversal of the base magnetic layer, and has the function of non-volatilely recording information of the multiple electron spin waves in conjunction with this magnetization reversal, and the information of the multiple electron spin waves is recorded as multiple states by the arranged plurality of recording magnetic bodies.

6. 3. The electron spin wave multiplex transmission device according to claim 1, wherein a gate electrode for applying a voltage is provided in the modulation section to form a collective difference gate.

7. 3. The electron spin wave multiplex transmission device according to claim 1, wherein a ferromagnetic layer for spin injection and amplification is provided in the modulation section to form a collective generation gate.

8. 3. The electron spin wave multiplex transmission device according to claim 1, wherein a wiring coupling section for coupling the electron spin waves is provided in the modulation section to form a set sum gate.

9. The electron spin wave multiplex transmission device of claim 1 or claim 2, characterized in that the introduction section has the function of generating the multiple electron spin waves by irradiating a laser on which information of the multiple polarized beam for optical communication is recorded, and has a multiple information transmission function by writing information corresponding to the multiple polarized beam for optical communication into the multiple electron spin waves.

10. 9. The multiplex transmission device for electron spin waves according to claim 1 or 2, characterized in that a parallel computer is constructed by comprising the collective difference gate according to claim 6, the collective generation gate according to claim 7, and the collective sum gate according to claim 8.

11. An electron spin wave multiplex transmission device as described in claim 5, characterized in that multiple recording magnetic bodies are provided vertically and horizontally in the surface direction of the recording section, and each of the recording magnetic bodies has the function of resonant switching by spin pumping due to the spin transfer effect from the multiple electron spin waves.

12. An electron spin wave multiplex transmission device as described in claim 11, which employs a structure that exhibits angular dependence due to the planar Hall effect in each of the recording magnetic materials, and has the function of reading information in the recording section by reading in-plane magnetization in the formation area of ​​the recording magnetic material.

13. Each of the recording magnetic materials has a structure that exhibits an anomalous Hall effect, An electron spin wave multiplex transmission device as described in claim 11, which has the function of reading information in the recording section by reading the perpendicular magnetization component in the formation area of ​​the recording magnetic material when each of the recording magnetic materials has a magnetization orientation perpendicular to the film surface.

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