Majority-decision logic device, photoelectric conversion device, optical communication logic device, and method for controlling majority-decision logic device

Abstract

A majority-decision logic device 1 comprises a non-magnetic semiconductor layer 10 made of a material that, when irradiated with light having at least two kinds of mutually different polarization states, generates electron spin waves having different phases corresponding to the polarization states. The non-magnetic semiconductor layer 10 comprises: three or more input portions to which a light signal is input; and at least one output portion that outputs a result of interference of the electron spin waves. The length of the distance between adjacent input portions as projected in the direction of vibration of the electron spin waves is an integer multiple of the wavelength of the electron spin waves.

Description

Majority logic device, photoelectric conversion device, optical communication logic device, and method for controlling majority logic device

[0001] The present invention relates to a majority logic device, an optoelectronic conversion device, an optical communication logic device, and a method for controlling a majority logic device.

[0002] Majority logic devices using spin waves (magnons) generated by continuous changes in the magnetic order of ferromagnetic materials have been disclosed (e.g., Non-Patent Document 1). Majority logic devices using spin waves (electron spin waves) generated by the sustained spin precession of free electrons due to an effective magnetic field are also known, and a majority logic device using spin polarization information of persistent spin helix (PSH) generated in a two-dimensional electron gas has been disclosed (e.g., Patent Document 1).

[0003] Special Publication 2015-518267

[0004] “Reconfigurable submicrometer spin-wave majority gate with electrical transducers” Talmelli et al. , Science Advances, vol. 6, issue 51, p. eabb4042, 18 December 2020 “Gate-controlled switching between persistent and inverse persistent spin helix states”, K. Yoshizumi, A. Sasaki, M. Kohda and J. Nitta”, APPLIED PHYSICS LETTERS 108, 132402 (2016) “Direct mapping of the formation of a persistent spin helix”, M.P. Walser, C. Reichl, W. Wegscheider, G. Salis, Nature Phys. advance online publication, 12 August 2012

[0005] The technology described in Non-Patent Document 1 requires that the input and output sections of the majority logic device be arranged in series along a linear ferromagnetic waveguide. In this case, the structure of the majority logic circuit is limited to one-dimensional, limiting the degree of freedom in arrangement. This results in low degree of freedom in circuit configuration, making it impossible to realize diverse circuits, such as two-dimensional structures. Furthermore, this technology uses a magnetic field generated by a high-frequency electrical signal to generate magnons. This requires the use of an electrical pulse magnetic field for input, which poses the challenge of making it difficult to integrate it with optical signals used in optical communications and other applications.

[0006] The technology described in Patent Document 1 uses electron spin waves (PSH) instead of magnons, but it also arranges logic input sections one-dimensionally. Furthermore, to prevent the electron spin waves from mixing in the logic input sections, it is necessary to provide a predetermined gap between each logic input section. Therefore, this technology also has the problem of limited flexibility in circuit configuration.

[0007] The present invention has been made in view of these problems, and its object is to realize a majority logic device that has a high degree of freedom in circuit configuration and good compatibility with optical signals.

[0008] To solve the above problems, one embodiment of the present invention provides a majority logic device having a non-magnetic semiconductor layer made of a material that generates electron spin waves with different phases depending on the polarization state when irradiated with light having at least two different polarization states. The non-magnetic semiconductor layer has three or more input sections for inputting optical signals and at least one output section for outputting the result of interference of the electron spin waves. The deviation of the distance between adjacent input sections projected in the direction of oscillation of the electron spin wave from an integer multiple of the wavelength of the electron spin wave is within 25% of the wavelength.

[0009] In an embodiment, the length of the distance between adjacent input sections projected in the vibration direction of the electron spin wave may be an integer multiple of the wavelength of the electron spin wave.

[0010] In one embodiment, the majority logic device may further include a waveguide layer stacked on the non-magnetic semiconductor layer directly or via another layer. This waveguide layer may have waveguides individually connected to each of the three or more input units directly or via another layer, and may have mirror sections at positions where the waveguides are individually connected to each of the three or more input units directly or via another layer, for guiding light that has passed through the waveguides to each of the input units.

[0011] In some embodiments, the waveguide may be oriented in a direction substantially perpendicular to the direction of oscillation of the electron spin waves.

[0012] In some embodiments, the output may be positioned an equal distance from each of the three or more inputs.

[0013] In an embodiment, the electron spin wave may be a reverse persistent spin rotation generated in a two-dimensional electron gas, and three or more inputs may be arranged in two dimensions on the non-magnetic semiconductor layer.

[0014] In one embodiment, when the Rashba spin-orbit interaction coefficient is α and the Dresselhaus spin-orbit interaction coefficient is β, the deviation between the absolute value of α and the absolute value of β may be within 15%.

[0015] In some embodiments, three or more inputs may be placed at each vertex of the polygon.

[0016] In one embodiment, three or more inputs may be located at each vertex of an equilateral triangle, and the output may be located at the centroid of the equilateral triangle.

[0017] In one embodiment, the electron spin wave may be an electron spin wave transformed into a helical spin mode by confining a two-dimensional electron gas in a one-dimensional wire structure, and the three or more input sections may be arranged in a one-dimensional direction on the non-magnetic semiconductor layer.

[0018] Another embodiment of the present invention is a photoelectric conversion device, which includes the above-described majority logic device and a magnetoresistive element that converts spin polarization of an output section into an electric signal.

[0019] Yet another embodiment of the present invention is also an optical communication device, which includes the majority logic device described above and an optical output element.

[0020] Yet another embodiment of the present invention is also an optical communication device, which includes the majority logic device described above and a wavelength multiplexing optical input element.

[0021] Another aspect of the present invention is a control method for a majority logic device having a non-magnetic semiconductor layer made of a material that generates electron spin waves having phases corresponding to the polarization states when irradiated with light having at least two mutually different polarization states, the non-magnetic semiconductor layer having three or more input sections for inputting optical signals and at least one output section for outputting the result of interference of the electron spin waves, wherein the deviation of the distance between adjacent input sections, projected in the oscillation direction of the electron spin waves, from an integer multiple of the wavelength of the electron spin wave is within 25% of the wavelength of the electron spin wave, and wherein the optical signals are modulated with right-handed circularly polarized light and left-handed circularly polarized light.

[0022] In one embodiment, the control method for a majority logic device may include compensating for the intensity of an optical signal input to the first input section to be greater than the intensity of an optical signal input to the second input section when the three or more input sections have a first input section and a second input section, and the distance between the first input section and the output section is longer than the distance between the second input section and the output section.

[0023] In one embodiment, the method for controlling a majority logic device may include inputting an optical signal that is always right-handed circularly polarized or left-handed circularly polarized to at least one of three or more input sections.

[0024] Another aspect of the present invention is a majority logic device. This majority logic device has a two-dimensional thin-wire structure in which an odd number of three or more one-dimensional thin-wire structures for signal input are configured to converge at a confluence point. Each of the one-dimensional thin-wire structures for signal input has a nonmagnetic semiconductor layer made of a material that generates electron spin waves with different phases depending on the polarization state when irradiated with light having at least two different polarization states. Each of the one-dimensional thin-wire structures for signal input has an input section prior to the confluence point for inputting an optical signal. The confluence point is provided with an output section for outputting the result of interference of the electron spin waves. The deviation of the distance between the confluence point and the input section of each one-dimensional thin-wire structure for signal input, projected in the oscillation direction of the electron spin wave, from an integer multiple of the wavelength of the electron spin wave is within 25% of the wavelength.

[0025] In one embodiment, the electron spin waves are inverse persistent spin gyrations generated in a two-dimensional electron gas.

[0026] In one embodiment, when the Rashba spin-orbit interaction coefficient is α and the Dresselhaus spin-orbit interaction coefficient is β, the deviation between the absolute value of α and the absolute value of β may be within 15%.

[0027] In one embodiment, the majority logic device may further include a confluent one-dimensional thin-wire structure extending from the confluence point. In this case, the confluent one-dimensional thin-wire structure may include an output section instead of the confluence point.

[0028] In one embodiment, a plurality of individual majority logic devices, each configured with the above-described majority logic device, may be provided. In this case, the merging one-dimensional thin-wire structures of the individual majority logic devices may be merged at a final merging point. An output section may be provided at this final merging point to output the result of interference of electron spin waves.

[0029] Another aspect of the present invention is a majority logic device. This majority logic device has a two-dimensional wire structure in which an odd number of three or more one-dimensional wire structures for signal input are configured to converge at a confluence point. Each of the one-dimensional wire structures for signal input has a nonmagnetic semiconductor layer made of a material that generates electron spin waves with different phases depending on the polarization state when irradiated with light having at least two different polarization states. Each of the one-dimensional wire structures for signal input has an input section before the confluence point for inputting an optical signal. The confluence point is provided with an output section for outputting the result of interference of the electron spin waves. The deviation of the distance between the confluence point and the input section of each one-dimensional wire structure for signal input from an integer multiple of the wavelength of the electron spin wave is within 25% of the wavelength.

[0030] In one embodiment, the Rashba spin-orbit interaction is the only spin-orbit interaction that acts on the electron spin wave.

[0031] In one embodiment, the majority logic device may further include a confluent one-dimensional thin-wire structure extending from the confluence point. In this case, the confluent one-dimensional thin-wire structure may be provided with an output section instead of the confluence point.

[0032] In one embodiment, a plurality of cellular majority logic devices may be provided, each of which is configured with the above-described majority logic device. In this case, the converging one-dimensional thin-wire structures of the plurality of cellular majority logic devices converge at a final confluence point. This final confluence point is provided with an output section that outputs the result of interference between electron spin waves.

[0033] Any combination of the above components, and conversion of the present disclosure into a method, device, system, recording medium, computer program, etc., are also valid aspects of the present disclosure.

[0034] The object of the present invention is to realize a majority logic device that has a high degree of freedom in circuit configuration and good compatibility with optical signals.

[0035] 1 is a schematic diagram of a majority logic device according to a first embodiment; FIG. 2 is a schematic diagram showing how the result of interference between three electron spin waves is read out at an output section and then the result is output; FIG. 3 is a schematic diagram illustrating the polarization state of light irradiated to an input section and the phase state of the electron spin wave after interference; FIG. 4 is a schematic diagram illustrating the polarization state of light irradiated to an input section and the phase state of the electron spin wave after interference; FIG. 5 is a schematic diagram illustrating the polarization state of light irradiated to an input section and the phase state of the electron spin wave after interference; FIG. 6 is a schematic diagram illustrating the polarization state of light irradiated to an input section and the phase state of the electron spin wave after interference; FIG. 7 is a schematic diagram illustrating the polarization state of light irradiated to an input section and the phase state of the electron spin wave after interference; FIG. 8 is a schematic diagram illustrating the polarization state of light irradiated to an input section and the phase state of the electron spin wave after interference; FIG. 9 is a schematic diagram illustrating a non-magnetic semiconductor layer in which the input section is arranged in a regular hexagonal shape and the output section is arranged at the center of gravity of this regular hexagon; FIG. 10 is a schematic diagram illustrating a non-magnetic semiconductor layer in which the input section and the output section are arranged in a one-dimensional direction; FIG. 11 is a schematic diagram illustrating how a wavelength-multiplexed optical signal to be input to a wavelength-multiplexed optical input element according to a fourth embodiment is generated; FIG. 12 is a schematic diagram of a wavelength-multiplexed optical input element used in the fourth embodiment; FIG. 13 is a schematic diagram illustrating a majority logic device according to a second embodiment; 1 is a schematic diagram of a majority logic device when one of the input sections is shifted in the x direction. FIG. 2 is a diagram showing simulation results of the time evolution of the phase of an electron spin wave at (x, y) = (0, 0) when one of the input sections is changed in the x direction. FIG. 3 is a diagram showing the polarization state of light and the phase state of an electron spin wave after interference when Δx = 0. FIG. 4 is a diagram showing the polarization state of light and the phase state of an electron spin wave after interference when Δx = 0.2λ. FIG. 5 is a diagram showing the polarization state of light and the phase state of an electron spin wave after interference when Δx = 0.4λ. FIG. 6 is a diagram showing simulation results of the phase of an electron spin wave at (x, y) = (0, 0) when one of the input sections is shifted in the x direction and y direction. FIG. 7 is a schematic diagram showing non-magnetic semiconductor layers in which input sections are arranged in a regular pentagon shape and output sections are arranged at the center of gravity of this regular pentagon. FIG. 8 is a schematic diagram of a majority logic device according to a sixth embodiment. FIG. 9 is a schematic diagram of a majority logic device according to a seventh embodiment. FIG. 10 is a schematic diagram of a majority logic device according to an eighth embodiment. FIG. 11 is a circuit diagram of a conventional majority logic device. 13A and 13B are schematic diagrams of majority logic devices according to a ninth embodiment and a tenth embodiment, respectively;

[0036] The present invention will be described below based on preferred embodiments with reference to the drawings. The embodiments are illustrative and do not limit the invention. Not all features or combinations thereof described in the embodiments are necessarily essential to the invention. Identical or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant description will be omitted where appropriate. Furthermore, the scale and shape of each part shown in each drawing are set for convenience to facilitate explanation and should not be interpreted as limiting unless otherwise specified. When terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are intended only to distinguish one configuration from another. Furthermore, some components that are not important for explaining the embodiments are omitted from each drawing.

[0037] [First embodiment] Fig. 1 schematically shows a majority logic device 1 according to a first embodiment. The majority logic device 1 includes a nonmagnetic semiconductor layer 10. The nonmagnetic semiconductor layer 10 includes input sections 20a, 20b, and 20c and an output section 30. In Fig. 1, the x-axis points rightward as one faces the page, and the y-axis points upward (the same applies hereinafter unless otherwise noted). The x-axis, however, is the vibration direction of electron spin waves, which will be described later, and is determined by the crystal orientation of the nonmagnetic semiconductor layer 10.

[0038] In the example of FIG. 1, the input units 20a, 20b, and 20c are arranged at the vertices of an equilateral triangle, and the output unit 30 is arranged at the center of gravity of this equilateral triangle.

[0039] That is, the output section 30 is disposed at an equal distance from each of the input sections 20a, 20b, and 20c.

[0040] The nonmagnetic semiconductor layer 10 is made of a material that generates electron spin waves with different phases depending on the polarization states of at least two types of light when irradiated with the light. Optical signals are input to the input sections 20 a, 20 b, and 20 c. The output section 30 reads out and outputs the interference results of the electron spin waves generated by the optical signals.

[0041] Hereinafter, the wavelength of the electron spin wave is represented as λ, and n is an integer. As shown in FIG. 1 , the length of the distance between input sections 20a and 20c projected in the oscillation direction of the electron spin wave (x-axis direction) is nλ. Similarly, the length of the distance between input sections 20b and 20c projected in the oscillation direction of the electron spin wave is also nλ. Furthermore, the length of the distance between input sections 20a and 20b projected in the oscillation direction of the electron spin wave is 2nλ. Thus, in the nonmagnetic semiconductor layer 10, the length of the distance between adjacent input sections projected in the oscillation direction of the electron spin wave is an integer multiple of the wavelength of the electron spin wave.

[0042] The nonmagnetic semiconductor layer 10 will be described in more detail. In the following example, it is assumed that there are two types of polarization states of irradiated light: right-handed circularly polarized light and left-handed circularly polarized light. When such light is irradiated onto the input sections 20a, 20b, and 20c, the nonmagnetic semiconductor layer 10 generates an electron spin wave with a phase of 0 for right-handed circularly polarized light and an electron spin wave with a phase of π for left-handed circularly polarized light. Hereinafter, an electron spin wave with a phase of 0 will be associated with a logical value of "0" (i.e., "false"), and an electron spin wave with a phase of π will be associated with a logical value of "1" (i.e., "true"). Therefore, in this case, right-handed circularly polarized light of the irradiated light corresponds to a logical value of 0, and left-handed circularly polarized light corresponds to a logical value of 1.

[0043] Electron spin waves generated by light irradiated onto input sections 20a, 20b, and 20c interfere with each other. At this time, electron spin waves with a phase of 0 and electron spin waves with a phase of π both strengthen each other through interference. Conversely, electron spin waves with one phase of 0 and the other phase of π weaken each other through interference. The results of the interference of the three electron spin waves are read out by the output section, and then output. Figure 2 shows a schematic diagram of this state.

[0044] Hereinafter, the logical values ​​corresponding to the polarization states of the light irradiated onto input units 20 a, 20 b, and 20 c will be expressed as vectors (20 a, 20 b, 20 c). For example, (20 a, 20 b, 20 c) = (0, 1, 0) indicates that the light irradiated onto input unit 20 a is right-handed circularly polarized light (electron spin wave phase 0, logical value 0), the light irradiated onto input unit 20 b is left-handed circularly polarized light (electron spin wave phase π, logical value 1), and the light irradiated onto input unit 20 c is right-handed circularly polarized light (electron spin wave phase 0, logical value 0).

[0045] The polarization state of the light irradiated to the input sections 20a, 20b, and 20c and the phase state of the electron spin wave after interference will be explained using the simulation results shown in Figures 3 to 6. The upper rows of Figures 3 to 6 show the polarization state of the light irradiated to the input sections 20a, 20b, and 20c. The black circles indicate that the irradiated light is right-handed circularly polarized (electron spin wave phase 0, logical value 0). The white circles indicate that the irradiated light is left-handed circularly polarized (electron spin wave phase π, logical value 1). The lower rows of Figures 3 to 6 show the phase of the electron spin wave after interference (specifically, 0.700 ns after irradiation). The white square shown near the center corresponds to the position of the output section 30.

[0046] 3 shows the case where (20a, 20b, 20c) = (0, 0, 0). In this case, as shown in the lower diagram, the phase of the electron spin wave after interference at the output section 30 is 0. In other words, the output section 30 reads out a logical value of 0. This value is the majority value for (20a, 20b, 20c) = (0, 0, 0).

[0047] 4 shows the case where (20a, 20b, 20c) = (0, 0, 1). In this case, as shown in the lower diagram, the phase of the electron spin wave after interference at the output section 30 is 0. In other words, the output section 30 reads out a logical value of 0. This value is the majority value for (20a, 20b, 20c) = (0, 0, 1).

[0048] 5 shows the case where (20a, 20b, 20c)=(0, 1, 1). In this case, as shown in the lower diagram, the phase of the electron spin wave after interference at the output section 30 is π. In other words, the output section 30 reads out a logical value of 1. This value is the majority value for (20a, 20b, 20c)=(0, 1, 1).

[0049] 6 shows the case where (20a, 20b, 20c) = (1, 1, 1). In this case, as shown in the lower diagram, the phase of the electron spin wave after interference at the output section 30 is π. In other words, the output section 30 reads out a logical value of 1. This value is the majority value for (20a, 20b, 20c) = (1, 1, 1).

[0050] 3 to 6, depending on the polarization state of light irradiated onto the input units 20a, 20b, and 20c, the majority value of the logical values ​​corresponding to that polarization state is read out by the output unit 30. Although not shown, the same applies to cases such as (20a, 20b, 20c)=(0, 1, 0), (1, 0, 0), (1, 0, 1), and (1, 1, 0).

[0051] Table 1 summarizes the relationship between the polarization states (corresponding logical values) of the three lights irradiated to the input sections 20a, 20b, and 20c and the phases (corresponding logical values) of the electron spin waves observed at the output section 30 after interference of the electron spin waves.

[0052] In this way, by arranging the input sections so that the distance between adjacent input sections projected in the vibration direction of the electron spin wave is an integer multiple of the wavelength of the electron spin wave, a majority logic device can be realized regarding the polarization states of the three light beams irradiated to input sections 20a, 20b, and 20c.

[0053] According to this embodiment, by providing a nonmagnetic semiconductor layer made of a material that generates electron spin waves with different phases depending on the polarization state when irradiated with light having at least two different polarization states, an optical signal having logical information represented by a polarization state can be converted into an electron spin wave having logical information represented by a spin state. Furthermore, by setting the distance between adjacent input sections projected in the oscillation direction of the electron spin wave to an integer multiple of the wavelength of the electron spin wave, a majority logic circuit for the above logical signal can be realized. The input sections of this majority logic circuit can be arranged in a two-dimensional direction. Furthermore, since an optical signal is used as the input rather than an electric pulse magnetic field, etc., it is highly compatible with optical communications, etc.

[0054] As described above, according to the present embodiment, the degree of freedom in circuit configuration is high, and it is not necessary to provide a predetermined gap between each of the logic input sections as in the technology described in Patent Document 1, and it is possible to realize a majority logic device that is well-matched with optical signals.

[0055] (Specific Example 1) The electron spin wave may be an inverse persistent spin gyration (iPSH) generated in a two-dimensional electron gas. In this case, each input section may be arranged in a two-dimensional direction on the nonmagnetic semiconductor layer 10.

[0056] For example, in a III-V semiconductor heterostructure, two types of spin-orbit interactions with different origins, namely, the absolute value of the Rashba spin-orbit interaction coefficient α and the absolute value of the Dresselhaus spin-orbit interaction coefficient β, are equalized, thereby determining the direction of the effective magnetic field and generating persistent spin gyration (broad sense) with suppressed spin relaxation. The persistent spin gyration (broad sense) state refers to a state in which the phase of the electron spin wave exhibits a striped pattern, allowing for efficient utilization of the oscillation of the electron spin wave while suppressing the diffusion of the electron spin wave. Here, the case of α = β is referred to as persistent spin gyration (narrow sense), in which the phase is constant in the direction of propagation of the electron spin wave and changes in the direction perpendicular to the propagation direction. Furthermore, the case of α = -β is referred to as inverse persistent spin gyration, in which the phase is constant in the direction perpendicular to the direction of propagation of the electron spin wave and changes in the direction of propagation.

[0057] In this case, the difference between the absolute value of the Rashba spin-orbit coupling coefficient α and the absolute value of the Dresselhaus spin-orbit coupling coefficient β may be within 15% of the average value of the absolute values. Preferably, the difference between the absolute value of α and the absolute value of β is within 10% of the average value of the absolute values. More preferably, the absolute value of α and the absolute value of β are equal to each other.

[0058] Table 2 shows previously reported Rashba spin-orbit interaction coefficients α and wavelengths λ of electron spin waves. λ is preferably 1 nm or more and 10 μm or less. While any material can be a candidate for a nonmagnetic semiconductor material for reverse persistent spin rotation, a material with a large λ is preferred for ease of manufacturing, and a material with a small λ is preferred for miniaturization. For example, tin sulfide (SnS) is thought to be useful.

[0059] Specific Example 2 In the example of FIG. 1 , the input sections 20 a, 20 b, and 20 c are arranged at the vertices of an equilateral triangle. However, this is not limiting, and the input sections may be arranged in a polygonal shape other than an equilateral triangle. FIG. 7 shows a nonmagnetic semiconductor layer 11 in which the input sections 20 d, 20 e, 20 f, 20 g, 20 h, and 20 i are arranged in a regular hexagon, and the output section 31 is arranged at the center of gravity of this regular hexagon. In the nonmagnetic semiconductor layer 11 as well, the length obtained by projecting the distance between adjacent input sections in the vibration direction of the electron spin wave (x-axis direction) is an integer multiple (nλ or 2nλ) of the wavelength of the electron spin wave.

[0060] (Specific Example 3) The electron spin wave may be an electron spin wave transformed into a helical spin mode by the confinement of a two-dimensional electron gas in a one-dimensional wire structure. Examples of electron spin waves transformed into a helical spin mode include an inverse persistent spin gyration state and a state in which only the Rashba spin-orbit interaction is active. Here, the state in which only the Rashba spin-orbit interaction is active refers to a state in which the absolute value of the Rashba spin-orbit interaction coefficient α is 10 times or more the absolute value of the Dresselhaus spin-orbit interaction coefficient β. In this case, each input section may be arranged in a one-dimensional direction on a nonmagnetic semiconductor layer. Examples of one-dimensional wire structures in the inverse persistent spin gyration state include a GaAs / AlGasAs quantum well and an InGaAs / InAlAs quantum well. Examples of one-dimensional wire structures in which only the Rashba spin-orbit interaction is active include an InGaAs / InAlAs quantum well.

[0061] 8 shows a nonmagnetic semiconductor layer 12 in which the input sections 20j, 20k, and 20l and the output section 32 are arranged in one dimension (x-axis direction). In the nonmagnetic semiconductor layer 12, too, the length obtained by projecting the distance between adjacent input sections onto the oscillation direction of the electron spin wave (i.e., the x-axis direction) is an integer multiple (nλ) of the wavelength of the electron spin wave.

[0062] [Second Embodiment] Another embodiment of the majority logic device further includes a waveguide layer stacked on the non-magnetic semiconductor layer directly or via another layer. This waveguide layer has waveguides individually connected to each of the three or more input units directly or via another layer. The majority logic device has mirror units at positions (hereinafter also referred to as "ends") where the waveguides are individually connected to each of the three or more input units directly or via another layer, for guiding light that has passed through the waveguides to each input unit.

[0063] FIG. 11 shows a schematic diagram of a device having a non-magnetic semiconductor layer on which a waveguide layer is laminated via another layer. This device has a structure in which a non-magnetic semiconductor layer, a cladding layer, a waveguide layer, and a cladding layer are laminated in this order on a substrate. The material of the waveguide is selected so that light of the wavelength to be used can pass through. The material of the cladding layer and the portion of the waveguide layer other than the waveguide is selected so that it has a lower refractive index than the material of the waveguide (core). If the waveguide is a Si waveguide, infrared laser light may be used. In this case, the portion of the waveguide layer other than the Si waveguide and the cladding layer are made of SiO ２ InGaAs may be used for the nonmagnetic semiconductor layer. When GaAs is used for the nonmagnetic semiconductor layer, a polymer waveguide made of ultraviolet curable resin may be used instead of the Si waveguide.

[0064] An optical signal (pump light) passes through the waveguide and, when it reaches a position tangent to the input section of the nonmagnetic semiconductor layer (e.g., the three vertices of an equilateral triangle), is deflected by a mirror, e.g., a 45° mirror, and injected into the three input sections. In the nonmagnetic semiconductor layer, right-handed circularly polarized pump light generates an electron spin wave with a phase of 0, while left-handed circularly polarized pump light generates an electron spin wave with a phase of π. The wavelength λ of the electron spin wave does not depend on the wavelength of the pump light (see the λ value in Table 2). In the case of a Si waveguide, the sidewall and the 45° mirror may be formed by separate etching processes. The 45° mirror processing at the end of the Si waveguide may be performed by anisotropic etching using TMAH on the Si(001) surface and KOH on the Si(110) surface.

[0065] In this embodiment, the waveguide may be arranged in a direction approximately perpendicular to the oscillation direction of the electron spin wave. As will be described later, in the majority logic device of the present invention, the tolerance for misalignment is greater in the perpendicular direction (y direction) than in the oscillation direction of the electron spin wave (x direction). Since the misalignment of the 45° mirror processing is greater than the misalignment of the waveguide, it is preferable to arrange the waveguide in the y direction.

[0066] [Third Embodiment] The third embodiment is a photoelectric conversion device. In the above-described majority logic device, the spin polarization of electron spin waves is output from the output section as the output logic value. In contrast, a photoelectric conversion device equipped with a majority logic circuit can be realized by converting this spin polarization into an electrical signal using, for example, a magnetoresistive element (MR element). That is, this embodiment is a photoelectric conversion device equipped with the majority logic device of the first or second embodiment and a magnetoresistive element that converts the spin polarization of the output section of the majority logic device into an electrical signal.

[0067] [Fourth Embodiment] The fourth embodiment is an optical communication logic device. This optical communication logic device includes the majority logic device of the first or second embodiment and an optical output element. The optical output element may be configured to irradiate linearly polarized light as a probe light and detect changes in the polarization state of transmitted light / reflected light due to the Faraday effect / Kerr effect. If it is desired to use the output signal in addition to detection, the polarized light may be separated by a polarizing beam splitter (PBS), converted into an electrical signal by a photodiode or the like, and then differentially amplified, as in reading a magneto-optical disk, for example.

[0068] In this embodiment, the optical communication logic device may include the majority logic device of the first or second embodiment and a wavelength-multiplexed optical input element. In this case, the wavelength-multiplexed optical input element may be, for example, an arrayed waveguide grating (AWG) device including an input waveguide, a slab waveguide, an optical waveguide array, a slab waveguide, and an output waveguide group, as schematically shown in Fig. 10. Here, the wavelength-multiplexed optical input element functions as an optical demultiplexer that splits a wavelength-multiplexed optical signal into a plurality of single-wavelength optical signals.

[0069] FIG. 9 shows a schematic diagram of how a wavelength-multiplexed optical signal input to the input waveguide of an AWG device is generated. First, three laser diodes LD1, LD2, and LD3 emit linearly polarized laser light beams with wavelengths λ1, λ2, and λ3, respectively. These linearly polarized laser light beams are converted to right-handed circular polarization by a quarter-wave plate (Q). These beams are then modulated by EO Modulators 1, 2, and 3, respectively, using electrical signals 1, 2, and 3, to produce left- and right-handed circularly polarized modulated signals. Each of the left- and right-handed circularly polarized modulated signals is multiplexed by an optical multiplexer, passes through an optical fiber as a wavelength-multiplexed optical signal, and inputs to the input waveguide of the AWG device shown in FIG. 10. The wavelength-multiplexed optical signal input to the AWG device is wavelength-separated and output, resulting in pump light that reproduces the left- and right-handed circularly polarized modulated signals output from each EO modulator.

[0070] FIG. 10 shows a schematic diagram of the AWG device used in this embodiment. The entire AWG device is formed on a silicon substrate and includes an input waveguide, an optical waveguide array, two slab waveguides, and a group of output waveguides. Light input to the input waveguide is wavelength-separated, and a left- and right-handed circularly polarized modulated signal is regenerated and output as pump light from the group of output waveguides. When the majority logic device is the second embodiment, the pump light λ1, λ2, and λ3 pass through the waveguides and reach a position where they contact the input sections of the nonmagnetic semiconductor layer (e.g., three points of an equilateral triangle). They are then deflected by a 45° mirror and injected into the three input sections. In the nonmagnetic semiconductor layer, right-handed circularly polarized pump light generates an electron spin wave with a phase of 0, and left-handed circularly polarized pump light generates an electron spin wave with a phase of π. The wavelength λ of the electron spin wave does not depend on the wavelength of the pump light (see the λ value in Table 2).

[0071] [Fifth Embodiment] The fifth embodiment is a method for controlling a majority logic device. This majority logic device has a non-magnetic semiconductor layer made of a material that generates electron spin waves having a phase corresponding to the polarization states when irradiated with light having at least two different polarization states. This non-magnetic semiconductor layer has three or more input sections for inputting optical signals and at least one output section for outputting the result of interference of the electron spin waves. The deviation of the distance between adjacent input sections, projected in the direction of oscillation of the electron spin waves, from an integer multiple of the wavelength of the electron spin waves is within 25% of the wavelength. This majority logic device generates optical signals modulated with right-handed circularly polarized light and left-handed circularly polarized light.

[0072] According to this embodiment, the majority logic device can be controlled in a variety of ways.

[0073] (Control Example 1) Consider a case where the plurality of input units of the majority logic device described above have a first input unit and a second input unit, and the distance between the first input unit and the output unit is longer than the distance between the second input unit and the output unit. In this case, control may be performed to compensate for the intensity of the optical signal input to the first input unit to be greater than the intensity of the optical signal input to the second input unit. By controlling the majority logic device in this way, it is possible to compensate for the difference in attenuation of the optical signal due to the difference in the distance between the input unit and the output unit.

[0074] (Control Example 2) An optical signal that is always right-handed circularly polarized or left-handed circularly polarized may be controlled to be input to at least one of the multiple input units of the majority logic device. For example, by inputting a right-handed circularly polarized optical signal (i.e., logical value 0) to one of the three input units, an AND circuit with two remaining inputs can be realized. Alternatively, by inputting a left-handed circularly polarized optical signal (i.e., logical value 1) to one of the three input units, an OR circuit with two remaining inputs can be realized. Furthermore, to realize a majority logic circuit with an even number of input units that outputs the input with the greater number of inputs when the number of inputs is equal between 0 and 1, and outputs 0 when the number of inputs is equal between 0 and 1, one additional input unit may be added and controlled to input a right-handed circularly polarized optical signal (i.e., logical value 0).

[0075] According to this control example, various types of logic circuits can be realized.

[0076] The present invention has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of the respective components and treatment processes, and that such modifications are also within the scope of the present invention.

[0077] (Variation 1) In the above embodiment, the distance between adjacent input units projected in the vibration direction of the electron spin wave was an integer multiple of the wavelength of the electron spin wave. However, it is considered that this length does not necessarily have to be an exact integer multiple of the wavelength of the electron spin wave. To verify this, the inventors performed the following simulation.

[0078] FIG. 12 shows a nonmagnetic semiconductor layer 13 (similar to FIG. 1 ) equipped with input sections 20m, 20n, and 20o and an output section 33. The input sections 20m, 20n, and 20o are located at the vertices of an equilateral triangle, and the output section 33 is located at the center of gravity of the triangle. The distance between the input sections 20m and 20n and the distance between the input sections 20n and 20o projected in the oscillation direction of the electron spin wave (x-axis direction) is λ. Note that FIG. 12 shows an inverted arrangement compared to FIG. 1 , but there is no essential difference between the two. Black circles indicate that the irradiated light is right-handed circularly polarized (electron spin wave phase 0, logic value 0). White circles indicate that the irradiated light is left-handed circularly polarized (electron spin wave phase π, logic value 1). In the initial state of FIG. 12 (time t = 0.000 ns), the polarization state is (20m, 20n, 20o) = (0, 1, 1).

[0079] In the following, we consider the case where the input unit 20n is shifted by Δx in the x direction. In this way, we verify by simulation whether a majority logic circuit can be correctly realized when the arrangement of the input units 20m, 20n, and 20o is shifted from an equilateral triangle.

[0080] 13 shows the simulation results of the time evolution of the phase of the electron spin wave at (x, y) = (0, 0) when the input section 20n is changed in the x direction. The horizontal axis represents the ratio Δx / λ of the shift Δx of the input section 20n to the wavelength λ, and the vertical axis represents time t (ns). As shown in the figure, when Δx / λ = 0, 1, or 2, the phase of the electron spin wave is π, i.e., the logical value is 1 (in this case, the majority logic is correctly established). When Δx / λ = 0.5 or 1.5, the phase of the electron spin wave is 0, i.e., the logical value is 0 (in this case, the majority logic is incorrect).

[0081] Figure 14 shows the polarization state of light irradiated to input sections 20m, 20n, and 20o and the phase state of the electron spin wave after interference when Δx = 0. The upper row shows the polarization state of light irradiated to each input section. The lower row shows the phase of the electron spin wave after interference (time t = 1.000 ns) (the white circle shown near the center corresponds to the position of output section 33). As shown in the figure, after interference of the electron spin wave, the logical value at the position of output section 33 is 1. This indicates that majority logic is realized for (20m, 20n, 20o) = (0, 1, 1).

[0082] 15 shows the polarization state of light irradiated onto input sections 20m, 20n, and 20o and the phase state of the electron spin wave after interference when Δx = 0.2λ. As shown in the figure, after interference of the electron spin wave, the logical value at the position of output section 33 is 1. Therefore, it can be seen that majority logic is realized for (20m, 20n, 20o) = (0, 1, 1) in this case as well.

[0083] 16 shows the polarization state of light irradiated onto input sections 20m, 20n, and 20o and the phase state of the electron spin wave after interference when Δx = 0.4λ. As shown in the figure, after interference of the electron spin wave, the logical value at the position of output section 33 is 0. Therefore, in this case, it can be seen that the majority logic is not correctly realized for (20m, 20n, 20o) = (0, 1, 1), and an error has occurred.

[0084] As can be seen from the above simulation results, in such an equilateral triangular arrangement, it is expected that a correct majority logic circuit can be realized even if one of the input sections is shifted in the x direction by, for example, about 25%.

[0085] 17 shows the simulation results of the phase of the electron spin wave at (x, y) = (0, 0) when the input section 20n is shifted in the x and y directions. The horizontal axis represents the ratio Δx / λ of the shift Δx in the x direction to the wavelength λ, and the vertical axis represents the ratio Δy / λ of the shift Δy in the y direction to the wavelength λ.

[0086] As shown in the figure, the phase changes with respect to the displacement in the x direction, and the phase inverts every half wavelength. On the other hand, the phase does not change with respect to the displacement in the y direction, and only the amplitude changes. Therefore, with regard to the realization of a majority logic circuit, it is considered that the tolerance for displacement in the y direction is relatively higher than that for displacement in the x direction.

[0087] 18 shows an example in which five input sections 20p, 20q, 20r, 20s, and 20t are arranged at the vertices of a regular pentagon, and the output section 34 is arranged at the center of gravity of the regular pentagon. Here, the length of the distance between input sections 20p and 20s projected in the oscillation direction of the electron spin wave (x-axis direction) is assumed to be twice the wavelength λ of the electron spin wave (2λ). Here, if the distance between the center of each input section (each vertex of the regular pentagon) and the center of the output section 34 (center of gravity of the regular pentagon) is r, then 2λ = r cos 54°. In this case, the length of the distance between input sections 20t and 20s projected in the oscillation direction of the electron spin wave (x-axis direction) is r cos 18° ≒ 3.23λ. In other words, the distance between input sections 20t and 20s projected in the vibration direction (x-axis direction) of the electron spin wave is shifted by approximately 0.23λ in the x-direction from the nearest integral multiple of the wavelength (3λ). This shift (approximately 23% of wavelength λ) is within 25% of wavelength λ. Therefore, even if each input section is arranged at each vertex of a regular pentagon in this way, it is believed that a correct majority logic circuit can be realized.

[0088] (Variation 2) In the examples described so far, the output unit has been set at a position where the distance between the output unit and the input unit projected in the oscillation direction of the electron spin wave is an integer multiple of the wavelength of the electron spin wave. Alternatively, the output unit can also be set at a position where the distance between the output unit and the input unit projected in the oscillation direction of the electron spin wave is an integer plus 1 / 2 times the wavelength of the electron spin wave. This makes it possible to obtain an output in which NOT is applied to majority logic. In this case, the difference in attenuation of the optical signal due to the difference in the distance between the input unit and the output unit, as described in Control Example 1, may be compensated for, if necessary.

[0089] Furthermore, by providing two or more output sections, it is possible to simultaneously obtain a majority logic output and its NOT output, or to combine two or more outputs to improve accuracy.

[0090] Sixth Embodiment In a one-dimensional wire structure formed from a semiconductor quantum well, electron spin waves with a defined phase state can be generated by irradiating polarized light onto electrons in the one-dimensional wire structure. Furthermore, electron spin waves with a defined phase state can be input from an adjacent one-dimensional wire structure. The generated or input electron spin waves propagate within the one-dimensional wire structure. The electron spin waves can take the following states depending on the type and magnitude of the spin-orbit interaction acting on them:

[0091] The PSH (persistent spin gyration) state is realized when the strength α of the Rashba spin-orbit interaction and the strength β of the Dresselhaus spin-orbit interaction are equal (α = β). At this time, the direction of the effective magnetic field created by the spin-orbit interaction is constant regardless of the direction of electron movement. Therefore, the spin precession is not affected by electron scattering, resulting in a state in which spin relaxation is suppressed. Specifically, coherent spin rotation continues in the [1 -1 0] direction of the crystal, and in the [1 1 0] direction perpendicular to this, a state in which spin relaxation is suppressed, in which the spin direction propagates without rotating.

[0092] The iPSH (inverse persistent spin gyration) state is realized when the sign of the strength of the Rashba spin-orbit interaction is reversed and becomes equal to the strength of the Dresselhaus spin-orbit interaction (α = -β). In this iPSH state, the direction of the effective magnetic field changes by 90 degrees relative to the PSH state, and the spin precession state changes to a state without spin precession. Specifically, the spin direction propagates without rotation in the [1 -1 0] direction of the crystal, while coherent spin rotation is sustained in the perpendicular [1 1 0] direction.

[0093] In the above description, the PSH (permanent spin swirl) state is defined as a state where α = β, and the iPSH state is defined as a state where α = -β. In actual embodiments, the absolute values ​​of α and β do not need to be strictly equal in either the PSH state or the iPSH state. For example, in the experimental example of realizing PSH in Non-Patent Document 3, α and β (however, in Reference 3, β is β) １ -β ３ ) are defined as α = (1.6_2.3) × 10 －１３ eVm, β １ -β ３ = (1.9 - 2.6) x 10 －１３ eVm, and the magnitude of the absolute values ​​of the two differs by 10% or more. However, even in this case, a striped spin pattern, which is a condition for PSH, can be formed. Therefore, even if the absolute values ​​of α and β differ by about 10%, the PSH state and the iPSH state can be realized. Furthermore, according to the inventors' considerations, it was found that a difference in the absolute values ​​of α and β of about 15% or less is acceptable.

[0094] Another characteristic state is a state where only the Rashba spin-orbit interaction acts as the spin-orbit interaction (|α|≧10|β|).

[0095] Here, the strength β of the Dresselhaus spin-orbit interaction is a specific value determined by the material, while the strength α of the Rashba spin-orbit interaction is a value that varies depending on the carrier concentration. The carrier concentration can be controlled by the amount of impurity doped into the one-dimensional wire structure, or by providing electrodes on the one-dimensional wire structure and applying a voltage to the electrodes. Two examples are shown below.

[0096] The first aspect is a one-dimensional wire structure in which spin-orbit interaction is active, resulting in an iPSH state. In this case, a quantum well having a one-dimensional wire structure through which electrons propagate is arranged such that the [1 1 0] direction of the crystal is the long axis (x-axis) direction, and the [1 -1 0] direction is the y-axis direction perpendicular to the x-axis. When the one-dimensional wire structure is in the iPSH state, electrons propagate while maintaining coherent spin rotation. In the first aspect, the distance refers to the distance projected in the x-direction.

[0097] The second aspect is a one-dimensional thin-wire structure in which only the Rashba spin-orbit interaction is active. In this case, the long axis (x-axis) can be determined regardless of the crystal orientation, and the y-axis can be set perpendicular to the x-axis. When the one-dimensional thin-wire structure is in a state in which only the Rashba spin-orbit interaction is active, electrons propagate while maintaining coherent spin rotation. In the second aspect, the distance refers to the distance on the xy plane.

[0098] Such a one-dimensional wire structure can be fabricated as follows (see, for example, Non-Patent Document 2). Specifically, in the example of Non-Patent Document 2, an InAlAs / InGaAs / InAlAs quantum well structure is epitaxially grown on an InP substrate using metalorganic chemical vapor deposition (MOCVD), and then a one-dimensional wire structure in the [1 1 0] direction is fabricated by photolithography and etching. The films are stacked in the following order starting from the InP substrate: 200 nm In ０．５２ Al ０．４８ As 6nm In ０．５２ Al ０．４８ As (1.2 × 10 １８ cm －３ Si doping) 6 nm In ０．５２Al ０．４８ As 7nm In ０．５３ Ga ０．４７ As quantum well 6nm In ０．５２ Al ０．４８ As 6nm In ０．５２ Al ０．４８ As (3.2 × 10 １８ cm －３ Si doping) 10 nm In ０．５２ Al ０．４８ As where the gate insulating layer (5 nm Al ２ O3 / 95nm HfO ２ ), and a gate electrode (10 nm Cr / 100 nm Au) are used. The carrier concentration at which the iPSH state is reached is 1.23 × 10 １６ m －２ is.

[0099] The first mode (iPSH state) will be described. Fig. 19 schematically shows a majority logic device 2 of this mode (sixth embodiment). Signal input one-dimensional thin-wire structures 40a, 40b, and 40c each include input sections 41a, 41b, and 41c that input optical signals before a junction 42. The signal input one-dimensional thin-wire structures join at the junction to form a two-dimensional thin-wire structure.

[0100] The junction 42 is provided with an output section 43 that outputs the result of interference of the electron spin waves.

[0101] The distance between the confluence 42 and the input portions 41a, 41b, and 41c of the one-dimensional thin-wire structures 40a, 40b, and 40c for signal input, projected in the direction of oscillation of the electron spin wave, is an integer multiple of the wavelength λ. In the example of Figure 19, the distance between the input portions 41a, 41b, and 41c of the one-dimensional thin-wire structures 40a, 40b, and 40c for signal input, projected in the direction of oscillation of the electron spin wave, is lλ, mλ, and nλ, respectively (l, m, and n are natural numbers). For example, with respect to a circumference of a radius 2λ centered at the confluence 42, the intersection of a line passing through the confluence and extending in the X-axis direction with the circumference may be designated as 41a, and the intersections of two lines passing through the confluence and forming an angle of 60° with the X-axis with the circumference may be designated as 41b and 41c.

[0102] In this way, by adjusting the distance between the confluence 42 and each input section 41a, 41b, 41c of the one-dimensional thin wire structures 40a, 40b, 40c for signal input so that the length projected in the vibration direction of the electron spin wave is an integer multiple of the wavelength of the electron spin wave, a majority logic device can be realized regarding the polarization states of the three light beams irradiated to the input sections 41a, 41b, 41c.

[0103] In this aspect, the difference between the absolute value of the Rashba spin-orbit coupling coefficient α and the absolute value of the Dresselhaus spin-orbit coupling coefficient β may be within 15% of the average value of the absolute values. Preferably, the difference between the absolute value of α and the absolute value of β is within 10% of the average value of the absolute values. More preferably, the absolute value of α and the absolute value of β are equal to each other.

[0104] According to this embodiment, a majority logic circuit can be realized using a one-dimensional wire structure including a non-magnetic semiconductor layer made of a material that generates electron spin waves having different phases depending on the polarization state when irradiated with light having at least two different polarization states.

[0105] The distance between the input portions 41a, 41b, and 41c of the one-dimensional thin-wire structures 40a, 40b, and 40c for signal input, projected in the vibration direction of the electron spin wave, is preferably an integer multiple of the wavelength λ. However, this may deviate slightly from the integer multiple of the wavelength. As shown in the above-mentioned variant 1, even if this length deviates from the integer multiple of the wavelength by about 25%, it is expected that the majority logic circuit can be correctly realized.

[0106] 19, the majority logic device 2 is configured with three one-dimensional thin wire structures for signal input. However, this number is not limited to three, and may be any odd number of wires equal to or greater than three.

[0107] 20 schematically shows a majority logic device 3 according to a seventh embodiment. The majority logic device 3 includes three one-dimensional thin-wire structures 40a, 40b, and 40c for signal input, and a converging one-dimensional thin-wire structure 44 extending from a converging point 42. In the majority logic device 3, instead of the output unit 43 provided at the converging point 42 of the majority logic device 2 in FIG. 19, the output unit 431 is provided in the converging one-dimensional thin-wire structure 44. The rest of the configuration of the majority logic device 3 is the same as that of the majority logic device 2.

[0108] According to this embodiment, in a majority logic circuit using a one-dimensional thin-wire structure for signal input, the degree of freedom of the output position can be increased.

[0109] Eighth Embodiment Figure 21 shows a schematic diagram of a majority logic device 4 according to an eighth embodiment. The majority logic device 4 includes a plurality of majority logic devices 3 according to the seventh embodiment. Hereinafter, in this specification, the plurality of majority logic devices 3 constituting this embodiment will be referred to as "cellular majority logic devices." In other words, the majority logic device 4 includes three cellular majority logic devices 45a, 45b, and 45c.

[0110] The confluence one-dimensional thin-wire structures of the three cellular majority logic devices converge at one confluence point 46. Hereinafter, in this specification, the point where all the cellular majority logic devices converge in this embodiment will be referred to as the "final confluence point." In other words, the confluence one-dimensional thin-wire structures of the cellular majority logic devices 45a, 45b, and 45c converge at one final confluence point 46.

[0111] At the final junction 46, an output section 432 is provided that outputs the result of interference of the electron spin waves.

[0112] 21, the majority logic device 4 is composed of three cellular majority logic devices. However, this number is not limited to three, and any number of cellular majority logic devices may be used.

[0113] According to this embodiment, a majority logic device can be realized with respect to the polarization state of light irradiated onto the input section of each cellular majority logic device.

[0114] For comparison, FIG. 22 shows a conventional 9-input majority logic device formed using AND circuits and OR circuits. This 9-input majority logic device is configured by combining four 3-input majority logic devices. In this configuration, the calculation results (majority results) output from the three first-stage 3-input majority logic devices are input to the second-stage 3-input majority logic device, and the final majority result is output. However, in this case, as shown in the figure, if five 0s and four 1s are input, the final majority result should be 0, but the incorrect result of 1 is output. This is an unavoidable issue in multi-stage digital circuits.

[0115] In contrast to this, according to this embodiment, a correct result can be obtained no matter which value is input to which input section of the majority logic device 4 in Fig. 21. This is an advantage of using the interference of electron spin waves generated by optical signals, and cannot be realized with multi-stage digital circuits.

[0116] [Ninth embodiment] The second mode (a state in which only the Rashba spin-orbit interaction is active) will now be described. Figure 23 schematically shows a majority logic device 5 of this mode (ninth embodiment). The majority logic device 5 includes three signal input one-dimensional thin-wire structures 40d, 40e, and 40f. The signal input one-dimensional thin-wire structures 40d, 40e, and 40f include input sections 41d, 41e, and 41f, respectively, that input optical signals before the junction 42.

[0117] The junction 42 is provided with an output section 43 that outputs the result of interference of the electron spin waves.

[0118] The distance on the XY plane between the confluence point 42 and the input portions 41d, 41e, and 41f of the one-dimensional thin-wire structures 40d, 40e, and 40f for signal input is an integer multiple of the wavelength λ. In the example of Figure 23, the distances on the XY plane between the input portions 41d, 41e, and 41f of the one-dimensional thin-wire structures 40d, 40e, and 40f for signal input are lλ, mλ, and nλ, respectively (l, m, and n are natural numbers). For example, with respect to a circumference of a radius 2λ centered at the confluence point 42, the intersections of any line passing through the confluence and the circumference can be set as the input points 41d, 41e, and 41f.

[0119] In the second embodiment, the lifetime (relaxation time) of the electron spin waves is shorter than in the first embodiment, but the number of one-dimensional thin-wire structures that can be assembled at the confluence can be increased. Therefore, in the first embodiment, nine inputs must be implemented with two stages of three inputs using a cellular majority logic device, as shown in Figure 21, but in the second embodiment, nine inputs can also be implemented with one stage of nine inputs.

[0120] 24 schematically shows a majority logic device 6 according to a tenth embodiment. The majority logic device 6 includes three one-dimensional thin-wire structures 40d, 40e, and 40f for signal input, and a converging one-dimensional thin-wire structure 44 extending from a converging point 42. In the majority logic device 6, instead of the output unit 43 provided at the converging point 42 of the majority logic device 5 in FIG. 23, the output unit 431 is provided in the converging one-dimensional thin-wire structure 44. The rest of the configuration of the majority logic device 6 is the same as that of the majority logic device 5.

[0121] According to this embodiment, in a majority logic circuit using a one-dimensional thin-wire structure for signal input, the degree of freedom of the output position can be increased.

[0122] Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present invention. A new embodiment resulting from the combination has the combined effects of each of the combined embodiments and modifications.

[0123] The above describes the embodiments and modifications. When understanding the abstract technical ideas of the embodiments and modifications, the technical ideas should not be interpreted as being limited to the contents of the embodiments and modifications. The above-described embodiments and modifications are merely illustrative examples, and many design modifications, such as changes, additions, and deletions of components, are possible. In the embodiments, the contents in which such design modifications are possible are emphasized by adding the notation "embodiment." However, design modifications are also permitted even in contents not so notated.

[0124] The technology of the present disclosure is applicable to fields such as optical communications, photoelectric conversion systems, and network computers.

[0125] 1. Majority logic device, 2. Majority logic device, 3. Majority logic device, 4. Majority logic device, 5. Majority logic device, 6. Majority logic device, 10. Non-magnetic semiconductor layer, 11. Non-magnetic semiconductor layer, 12. Non-magnetic semiconductor layer, 13. Non-magnetic semiconductor layer, 20a. Input section, 20b. Input section, 20c. Input section, 20d. Input section, 20e. Input section, 20f. Input section, 20g. Input section, 20h. Input section, 20i. Input section, 20j. Input section, 20k. Input section, 20l. Input section, 20m. Input section, 20n. Input section, 20o. Input section, 20p. Input section, 20q...input section, 20r...input section, 20s...input section, 20t...input section, 30...output section, 31...output section, 32...output section, 33...output section, 34...output section, 40a...one-dimensional thin wire structure for signal input, 40b...one-dimensional thin wire structure for signal input, 40c...one-dimensional thin wire structure for signal input, 40d...one-dimensional thin wire structure for signal input, 40e...one-dimensional thin wire structure for signal input, 40f...one-dimensional thin wire structure for signal input, 41a...input section, 41b...input section, 41c...input section, 41d...input section, 41e...input section, 41f...input section, 42...junction, 43...output section, 431...output section, 432: Output section; 44: Confluence one-dimensional thin wire structure; 45a: Cellular majority logic device; 45b: Cellular majority logic device; 45c: Cellular majority logic device; 46: Final confluence point.

Claims

1. A majority logic device comprising a non-magnetic semiconductor layer made of a material that generates electron spin waves with different phases depending on the polarization state of at least two kinds of light that are irradiated with the non-magnetic semiconductor layer, the non-magnetic semiconductor layer having three or more input sections for inputting optical signals and at least one output section for outputting the results of interference of the electron spin waves, wherein the deviation of the distance between adjacent input sections projected in the direction of oscillation of the electron spin waves from an integer multiple of the wavelength of the electron spin waves is within 25% of the wavelength.

2. The majority logic device according to claim 1, wherein the length of the distance between adjacent input sections projected in the vibration direction of the electron spin wave is an integer multiple of the wavelength of the electron spin wave.

3. The majority logic device according to claim 1 or 2, further comprising a waveguide layer stacked on the non-magnetic semiconductor layer directly or via another layer, the waveguide layer having waveguides individually connected to each of the three or more input sections directly or via another layer, and having mirror sections at positions where the waveguides are individually connected to each of the three or more input sections directly or via another layer, for guiding light that has passed through the waveguides to each of the input sections.

4. The majority logic device according to claim 3, wherein said waveguide is arranged in a direction substantially perpendicular to the vibration direction of said electron spin waves.

5. A majority logic device according to claim 1 or 2, wherein the output section is positioned at an equal distance from each of the three or more input sections.

6. The majority logic device according to claim 1 or 2, characterized in that the electron spin wave is a reverse permanent spin rotation generated in a two-dimensional electron gas, and the three or more input sections are arranged in a two-dimensional direction on the non-magnetic semiconductor layer.

7. The majority logic device according to claim 6, characterized in that, when the Rashba spin-orbit interaction coefficient is α and the Dresselhaus spin-orbit interaction coefficient is β, the deviation between the absolute value of α and the absolute value of β is within 15% of the average value of the absolute values.

8. The majority logic device of claim 6, wherein the three or more inputs are located at each vertex of a polygon.

9. The majority logic device of claim 8, wherein the three or more input ports are located at the vertices of an equilateral triangle, and the output port is located at the center of gravity of the equilateral triangle.

10. A majority logic device according to claim 1 or 2, characterized in that the electron spin waves are electron spin waves that have been converted into a helical spin mode by confinement of a two-dimensional electron gas in a one-dimensional thin wire structure, and the three or more input sections are arranged in a one-dimensional direction on the non-magnetic semiconductor layer.

11. A photoelectric conversion device comprising: the majority logic device according to claim 1 or 2; and a magnetoresistive element that converts the spin polarization of the output section into an electric signal.

12. An optical communication logic device comprising: a majority logic device according to claim 1 or 2; and an optical output element.

13. An optical communication logic device comprising: a majority logic device according to claim 1 or 2; and a wavelength multiplexing optical input element.

14. A method for controlling a majority logic device having a non-magnetic semiconductor layer made of a material that generates electron spin waves having phases corresponding to at least two different polarization states when irradiated with light, the non-magnetic semiconductor layer having three or more input sections for inputting optical signals and at least one output section for outputting the results of interference of the electron spin waves, wherein the deviation of the distance between adjacent input sections, projected in the direction of oscillation of the electron spin waves, from an integer multiple of the wavelength of the electron spin waves is within 25% of the wavelength, wherein the optical signals are modulated with right-handed circularly polarized light and left-handed circularly polarized light.

15. The control method according to claim 14, wherein the three or more input sections have a first input section and a second input section, and when the distance between the first input section and the output section is longer than the distance between the second input section and the output section, the intensity of the optical signal input to the first input section is compensated to be greater than the intensity of the optical signal input to the second input section.

16. The control method according to claim 14, wherein an optical signal that is always clockwise circularly polarized or counterclockwise circularly polarized is input to at least one of the three or more input sections.

17. A majority logic device comprising a two-dimensional thin-wire structure configured such that three or more odd number of one-dimensional thin-wire structures for signal input converge at one confluence point, each of the one-dimensional thin-wire structures for signal input has a non-magnetic semiconductor layer made of a material that generates electron spin waves with different phases depending on the polarization state when irradiated with light having at least two mutually different polarization states, each of the one-dimensional thin-wire structures for signal input has an input section before the confluence point for inputting an optical signal, and an output section for outputting the result of interference of the electron spin waves at the confluence point, wherein the deviation of the length between the confluence point and each input section of the one-dimensional thin-wire structures for signal input projected in the vibration direction of the electron spin wave from an integer multiple of the wavelength of the electron spin wave is within 25% of the wavelength.

18. The majority logic device of claim 17, wherein the electron spin wave is a reverse persistent spin gyration generated in a two-dimensional electron gas.

19. The majority logic device according to claim 18, wherein, when the Rashba spin-orbit interaction coefficient is α and the Dresselhaus spin-orbit interaction coefficient is β, the deviation between the absolute value of α and the absolute value of β is within 15% of the average value of the absolute values.

20. A majority logic device having a two-dimensional thin wire structure configured so that three or more odd number of one-dimensional thin wire structures for signal input converge at one confluence point, each of the one-dimensional thin wire structures for signal input has a non-magnetic semiconductor layer made of a material that generates electron spin waves with different phases depending on the polarization state when irradiated with light having at least two mutually different polarization states, each of the one-dimensional thin wire structures for signal input has an input section before the confluence point for inputting an optical signal, and an output section for outputting the result of interference of the electron spin waves at the confluence point, and the deviation of the distance between the confluence point and the input section of each of the one-dimensional thin wire structures for signal input from an integer multiple of the wavelength of the electron spin wave is within 25% of the wavelength.

21. The majority logic device according to claim 20, wherein only the Rashba spin-orbit interaction acts as the spin-orbit interaction relating to the electron spin wave.

22. A majority logic device according to any one of claims 17 to 21, further comprising a converging one-dimensional thin wire structure extending from the converging point, wherein the output section is provided in the converging one-dimensional thin wire structure instead of the converging point.

23. A majority logic device comprising a plurality of cellular majority logic devices, each of which is constructed using the majority logic device described in claim 22, wherein the confluent one-dimensional thin wire structures of the plurality of cellular majority logic devices converge at a single final confluence point, and wherein the final confluence point is provided with an output section that outputs the result of interference of the electron spin waves.

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