Electron-spin-wave wavelength conversion device, calculation device, and electron-spin-wave phase modulation device

Abstract

An electron-spin-wave wavelength conversion device (100) according to the present invention comprises: a waveguide (101) that is formed from a compound semiconductor and that causes electron spin propagation in the X direction; and a first barrier layer (102) that is disposed on one side of the waveguide (101) in the Z direction, which intersects the X direction, and a second barrier layer (103) that is disposed on the other side of the waveguide (101) in the Z direction. The waveguide (101) is formed by connecting a first waveguide (104) and a second waveguide (105), the width W2 of the second waveguide (105) in the Y direction, which intersects the X direction and the Z direction, is narrower than the width W1 of the first waveguide (104), and the band gap energy of the first barrier layer (102) and the second barrier layer (103) is larger than that of the waveguide (101).

Description

Electron spin wave wavelength conversion device, arithmetic device, and electron spin wave phase modulation device

[0001] The present invention relates to an electron spin wave wavelength conversion device, an arithmetic unit, and an electron spin wave phase modulation device. This application claims priority to Japanese Patent Application No. 2024-151525, filed on September 3, 2024, the contents of which are incorporated herein by reference.

[0002] It is known that the spatial pattern drawn by electron spin polarization can be used as an information carrier with wave properties called an electron spin wave (Non-Patent Document 1). The inventors have developed a technology for optically observing electron spin waves, and it is expected that electron spin waves will be used in various materials, including semiconductors. Since the wavelength of an electron spin wave is a continuously changing parameter, assigning a different wavelength to each information carrier makes it possible to process a huge amount of information, enabling, for example, parallel computing using multiple information carriers simultaneously. In this case, a technology is required to easily and accurately control the assigned wavelength of the electron spin wave, but such a technology has not yet been established.

[0003] Y. Kunihashi et al., Nat. Commun. 7, 10722 (2016).

[0004] The present invention has been made in consideration of the above circumstances, and aims to provide an electron spin wave wavelength conversion device that enables the wavelength of an electron spin wave to be easily and accurately controlled, an arithmetic device equipped with the same, and an electron spin wave phase modulation device.

[0005] In order to solve the above problems, the present invention employs the following means.

[0006] (1) An electron spin wave wavelength conversion device according to one aspect of the present invention includes a waveguide made of a compound semiconductor and propagating electron spin in an X direction, a first barrier layer arranged on one side of the waveguide in a Z direction intersecting the X direction, and a second barrier layer arranged on the other side of the waveguide, wherein the waveguide is formed by connecting a first waveguide and a second waveguide, and the width of the second waveguide in a Y direction intersecting the X direction and the Z direction is narrower than the width of the first waveguide, and the material forming the first barrier layer and the second barrier layer has a larger band gap energy than the material forming the waveguide.

[0007] (2) In the wavelength conversion device of electron spin waves described in (1) above, it is preferable that one of the first barrier layer and the second barrier layer is made of AlGaAs and the other is made of AlAs, the material forming the waveguide is GaAs, and the thickness of the waveguide in the Z direction is 50 nm or less.

[0008] (3) In the electron spin wave wavelength conversion device described in (1) above, it is preferable that the material of the first barrier layer and the second barrier layer is AlGaAs, the material of the waveguide is GaAs, and the thickness of the waveguide in the Z direction is 50 nm or less.

[0009] (4) In the electron spin wave wavelength conversion device described in (1) above, it is preferable that the material of the first barrier layer and the second barrier layer is GaAs, the material of the waveguide is InAs, and the thickness of the waveguide in the Z direction is 50 nm or less.

[0010] (5) In the electron spin wave wavelength conversion device described in any one of (1) to (4) above, it is preferable that the thickness of the first barrier layer and the second barrier layer in the Z direction is 10 nm or more and 100 nm or less, and the thickness of the waveguide in the Z direction is 5 nm or more and 50 nm or less.

[0011] (6) Another aspect of the present invention provides a wavelength conversion device for electron spin waves, comprising a heterojunction between two different compound semiconductor layers, a waveguide that propagates electron spins in an X direction along the interface of the heterojunction, a first barrier layer disposed on one side of the waveguide in a Z direction that intersects with the X direction, and a second barrier layer disposed on the other side of the waveguide, the waveguide connecting a first waveguide and a second waveguide, and the width of the second waveguide is narrower than the width of the first waveguide at the interface of the heterojunction in a Y direction that intersects with the X direction.

[0012] (7) In the electron spin wave wavelength conversion device described in (6) above, one of the first barrier layer and the second barrier layer is made of InAs and the other is made of GaAs, and at least the region of the heterojunction interface made of InAs becomes the waveguide.

[0013] (8) In the wavelength conversion device of electron spin waves described in any one of (1) to (7) above, the first waveguide and the second waveguide may be connected via a third waveguide, and one end of the third waveguide may be connected to the first waveguide and the other end may be connected to the second waveguide, and the width in the Y direction may change continuously from the one end to the other end.

[0014] (9) In the electron spin wave wavelength conversion device described in any one of (1) to (8) above, the compound semiconductor may be a III-V group semiconductor.

[0015] (10) In the electron spin wave wavelength conversion device described in any one of (1) to (9) above, a plurality of the second waveguides may be connected to the first waveguide.

[0016] (11) A computing device according to one aspect of the present invention includes the electron spin wave wavelength conversion device according to any one of (1) to (10) above.

[0017] (12) An electron spin wave phase modulation device according to one aspect of the present invention includes the electron spin wave wavelength conversion device according to any one of (1) to (10) above.

[0018] According to the present invention, it is possible to provide an electron spin wave wavelength conversion device that enables easy and accurate control of the wavelength of an electron spin wave, an arithmetic device equipped with the same, and an electron spin wave phase modulation device.

[0019] 1A is a perspective view of an electron spin wave wavelength converter according to a first embodiment of the present invention. FIG. 1B is a perspective view of a waveguide constituting the electron spin wave wavelength converter of FIG. 1A. FIG. 1C is a diagram schematically showing an example of the crystal structure of a compound semiconductor constituting the waveguide. FIG. 1D is a diagram (left) showing a plan view of the electron spin wave wavelength converter from the Y direction, and a distribution diagram of electron band gap energy in the Z direction in the electron spin wave wavelength converter (right). FIG. 1E is a diagram schematically showing an effective magnetic field generated by an electric field caused by the crystal structure of the waveguide. FIG. 1F is a diagram schematically showing an effective magnetic field generated by an electric field caused by an energy band structure in the Z direction. FIG. 1G is a diagram schematically showing a combined effective magnetic field obtained by combining the effective magnetic fields of FIG. 4A and FIG. 4B. FIG. 1H is a diagram explaining electron spin waves propagating through a waveguide. FIG. 1I is a graph explaining the relationship between electron drift velocity and the wavelength of an electron spin wave. FIG. 1J is a diagram showing a plan view of a waveguide of Modification 1 from the Z direction. FIG. 1J is a diagram showing a plan view of a waveguide of Modification 2 from the Z direction. 10 is a diagram showing a change in wavelength of an electron spin wave of an electron propagating through a waveguide that is made up of three parts with different widths, in which a relatively thick part, a thin part, and a thick part are connected in this order. 11 is a diagram showing a simulation result of an example.

[0020] Hereinafter, an electron spin wave wavelength conversion device and a calculation device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show characteristic parts enlarged for the sake of clarity, and the dimensional ratios of each component may not be the same as in reality. Furthermore, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited to them and can be modified as appropriate within the scope of the present invention.

[0021] 1A is a perspective view of an electron spin wave wavelength converter 100 according to a first embodiment of the present invention. The electron spin wave wavelength converter 100 mainly includes a waveguide 101 for propagating electron spin waves, a first barrier layer 102, and a second barrier layer 103. The waveguide 101 is plate-shaped (flat) with a substantially flat main surface and extends in one direction (here, the X direction). In a direction (here, the Z direction) intersecting (preferably orthogonal to) the X direction, the first barrier layer 102 is disposed on one side (here, the upper side) of the waveguide 101, and the second barrier layer 103 is disposed on the other side (here, the lower side) of the waveguide 101.

[0022] 1B is a perspective view of the waveguide 101. The waveguide 101 is formed by coupling a first waveguide 104 and a second waveguide 105 that extend in one direction (here, the X direction). An end of the first waveguide 104 and an end of the second waveguide 105 in the X direction are coupled. The first waveguide 104 and the second waveguide 105 may be separate bodies, but are preferably integrated from the viewpoint of not interfering with the propagation of electron spin waves.

[0023] In the Y direction, which intersects (preferably orthogonal to) the X direction and the Z direction, the first waveguide 104 and the second waveguide 105 have different widths W. Here, the width W of the second waveguide ２ is the width W of the first waveguide １ 10 illustrates a case where the width is narrower.

[0024] The thickness T of the waveguide 101 in the Z direction is substantially uniform throughout. Furthermore, the thickness T may be any thickness that allows the material forming the waveguide to form a quantum well. For example, the thickness T of the waveguide in the Z direction is preferably 50 nm or less, more preferably 25 nm or less, and even more preferably 10 nm or less, and may be 5 nm or more. If the thickness T is within this range, the movement of propagating electrons can be substantially restricted to the XY plane. If the thickness T is greater than 50 nm, the characteristics approach those of a bulk material, which may not solve the problem of the present invention.

[0025] The waveguide 101 is made of a compound semiconductor with broken crystal field symmetry. The compound semiconductor is preferably a III-V semiconductor, such as GaAs, InAs, InP, or InSb. The compound semiconductor may be magnetic or non-magnetic, and is selected from materials with a smaller energy gap than the first barrier layer 102 and the second barrier layer 103.

[0026] 2 is a diagram schematically showing an example of the crystal structure of a compound semiconductor that constitutes the waveguide 101. Here, the case where the compound semiconductor is GaAs is shown as an example. GaAs has a zinc blende crystal structure as shown in FIG. 2. In the crystal structure of GaAs, each Ga is relatively positively charged and each As is relatively negatively charged, and an electric field is generated in the direction from each Ga to each As, resulting in a break in the symmetry of the crystal field as a whole. In this way, in a compound semiconductor in which the symmetry of the crystal field is broken, an electric field E １ occurs.

[0027] The waveguide 101 is sandwiched between a first barrier layer 102 and a second barrier layer 103 in the Z direction. The first barrier layer 102 is bonded to one main surface 101a of the waveguide extending in the XY plane, and the second barrier layer 103 is bonded to the other main surface 101b opposite to the one main surface 101a. The first barrier layer 102 may have any shape as long as it covers at least the one main surface 101a of the waveguide. The second barrier layer 103 may have any shape as long as it covers at least the other main surface 101b of the waveguide.

[0028] The material of the first barrier layer 102 and the material of the second barrier layer 103 may be the same or different from each other, and have a larger bandgap energy than the compound semiconductor that constitutes the waveguide 101. For example, if the waveguide 101 is made of GaAs, one of the first barrier layer 102 and the second barrier layer 103 can be made of AlGaAs, and the other can be made of AlAs or AlGaAs. Furthermore, if the waveguide 101 is made of InAs, the material of the first barrier layer 102 and the second barrier layer 103 can be selected from, for example, InP, AlAs, and GaAs.

[0029] The thickness of the first barrier layer 102 and the second barrier layer 103 is not particularly limited, but from the viewpoint of miniaturization, it is preferable to select the thickness from 10 nm or more and 100 nm or less.

[0030] 3 shows a plan view of the electron spin wave wavelength converter 100 from the Y direction (left diagram), and a distribution diagram of the band gap energy of electrons in the Z direction in the electron spin wave wavelength converter 100 (right diagram). The band gap energies of the first barrier layer 102 and the second barrier layer 103 act as energy barriers, and the wave function of the electrons is almost localized within the waveguide 101, and the region of electron motion is limited within the waveguide 101. An electric field E ２ occurs.

[0031] FIG. 4A shows the electric field E due to the crystalline structure of the waveguide 101. １ The effective magnetic field H １ is a diagram showing the effective magnetic field H １ is generated in a complexly tilted direction at each position in the crystal structure under the influence of the motion of electrons flowing in the waveguide 101, and acts on the rotation of the electron spin wave. This effect is called the Dresselhaus spin-orbit interaction.

[0032] FIG. 4B shows the electric field E due to the energy band structure (quantum well structure) in the Z direction of the waveguide. ２ The effective magnetic field H ２ is a diagram showing the effective magnetic field H ２ is the electric field in the Z direction E ２ This effect is called the Rashba spin-orbit interaction.

[0033] FIG. 4C shows two effective magnetic fields H １ , H ２ The combined effective magnetic field H (= H １ +H ２ ) is a diagram showing the effective magnetic field H １ , H ２4C, a composite effective magnetic field H tilted in one specific direction is obtained. The electron spins in the waveguide 101 perform precession with the direction of the composite effective magnetic field H as the axial direction.

[0034] 5 is a diagram illustrating an electron spin wave S propagating in the X direction in a waveguide 101 constituting an electron spin wave wavelength conversion device 100. Here, the first barrier layer 102 and the second barrier layer 103 are not shown. Electrodes 106c and 106d are connected to both ends 101c and 101d of the waveguide 101, respectively, and a voltage V is applied across the waveguide 101 via the electrodes 106c and 106d to generate an electric field. Each electron in the waveguide 101 moves under the action of this electric field, and the electron spin of each electron precesses with its axial direction aligned with the direction of the effective magnetic field H, causing the distribution of electron spin orientations to propagate as an electron spin wave S in the electric field direction.

[0035] The wavelength λ of the electron spin wave S differs when it propagates in the first waveguide 104 and when it propagates in the second waveguide 105. That is, when the electron spin wave S propagates from the first waveguide 104 side to the second waveguide 105 side, the wavelength λ of the electron spin wave S propagating in the second waveguide 105 ２ Wavelength λ ２ is the electron spin wave S propagating in the first waveguide 104. １ Wavelength λ １ On the other hand, when the electron spin wave S propagates from the second waveguide 105 side toward the first waveguide 104 side, the electron spin wave S propagating in the first waveguide 104 １ Wavelength λ １ is the electron spin wave S propagating in the second waveguide 105. ２ Wavelength λ ２ It will be shorter than

[0036] Ratio (W ２ / W １ If the ratio (W) is smaller than 0.1, the number of electrons that collide with the sidewall of the waveguide 101A increases, making it difficult to suppress the scattering of electrons due to the resistance from the sidewall. ２ / W １ ) is greater than 0.9, the width W １ and width W ２The difference between the wavelengths becomes smaller, and the wavelength conversion effect is weakened.

[0037] The influence of the width W of the waveguide on the wavelength λ of the electron spin wave S will be described. The wavelength λ of the electron spin wave is given by the following formula (1). The factors h / (2π), m, α, and β included in formula (1) are １ , β ３ , V ｄｒｉｆｔ , V Ｆｅｒｍｉ and represent the following physical quantities: h / (2π): reduced Planck constant (Dirac constant), m: effective mass of electron, α: constant of Rashba spin-orbit coupling, β １ , β ３ : Dresselhaus spin-orbit coupling constant.

[0038]

[0039] FIG. 6 shows the drift velocity V of electrons moving under the action of an electric field. ｄｒｉｆｔ and the wavelength λ of the electron spin wave. The horizontal axis of the graph is the Fermi velocity V Ｆｅｒｍｉ Drift velocity V ｄｒｉｆｔ The ratio (V ｄｒｉｆｔ / V Ｆｅｒｍｉ The vertical axis of the graph represents the wavelength λ of the electron spin wave. In the graph of FIG. 6, m in the above formula (1) is set to 0.067 m. ０ (m ０ is the rest mass of a free electron), and α is -1.75 × 10 －１３ (eVm), β １ to 1.70 x 10 －１３ (eVm), β ３ to 0.41 x 10 －１３ (eVm), the wavelength λ of the electron spin wave is the electron drift velocity V ｄｒｉｆｔ The curves are plotted as a function of .

[0040] Drift speed V ｄｒｉｆｔ is given by the following equation (2): j, e, n included in equation (2) Ｓ respectively represent the following physical quantities: j: current density, e: elementary charge, n Ｓ : Carrier density.

[0041]

[0042] As shown in the above equation (2), the drift velocity V ｄｒｉｆｔ is proportional to the current density j. The current density j is inversely proportional to the cross-sectional area of ​​the waveguide 101 through which the current (electrons) flows, and for example, the smaller the width W of the waveguide 101, the larger the current density j. Therefore, the wavelength λ of the electron spin wave is inversely proportional to the width W of the waveguide 101, and in the first waveguide 104 with a large width W, the wavelength λ of the electron spin wave is １ Conversely, in the first waveguide 104 with a small width W, the wavelength λ of the electron spin wave ２ will be longer.

[0043] 7 shows a first modification of the configuration of the waveguide 101. Fig. 7 is a plan view of a waveguide 101A of the first modification, viewed from the Z direction. In the waveguide 101A, a first waveguide 104 and a second waveguide 105 are connected via a third waveguide 107. The configuration is the same as that of the waveguide 101, except for the presence of the third waveguide 107.

[0044] The third waveguide 107 has one end 107a connected to the first waveguide 104 and the other end 107b connected to the second waveguide 105. The third waveguide 107 has a width W ３ Here, the width W changes continuously from one end 107a to the other end 107b. ３ 10 illustrates a case where the .lambda..times ...

[0045] Here, the width W of the one end side 107a ３ is the width W of the first waveguide 104 １ 1, the width W of the one end side 107a is equal to ３ is the width W １ Similarly, here, the width W of the other end side 107b may be ３ is the width W of the second waveguide 105 ２ 1, the width W of the other end 107b is equal to ３ is the width W ２ It may be larger.

[0046] In addition, although the case where both side surfaces 107c and 107d of the third waveguide 107 in the Y direction are flat is exemplified here, the both side surfaces 107c and 107d may be curved surfaces that are convex inward or curved surfaces that are convex outward as shown by the broken lines. ３ may vary nonlinearly with distance from the first waveguide 104 or the second waveguide 105.

[0047] In waveguide 101A, the presence of third waveguide 107 whose width changes continuously makes the change in width W gentler between first waveguide 104 and second waveguide 105. Therefore, at the connection portion between first waveguide 104 and second waveguide 105, the resistance that electrons experience from the sidewall of waveguide 101A can be reduced, and scattering of electrons at the sidewall can be suppressed.

[0048] Modification 2 relating to the configuration of the waveguide 101 is shown. Fig. 8 is a plan view of a waveguide 101B of modification 2 as viewed from the Z direction. In the waveguide 101B, a plurality of second waveguides 105 are coupled to one first waveguide 104. Here, the case where the number of coupled second waveguides 105 is two is illustrated as an example, but three or more may be coupled. The configuration other than the number of coupled second waveguides 105 is the same as the configuration of the waveguide 101.

[0049] The width W of each second waveguide 105 ２ can be individually set so that the electron spins S are converted into the desired wavelength, and may be the same or different from each other. The configuration of the waveguide 101B is the same as when the second waveguide 105 in the waveguide 101 is divided into multiple waveguides, and the current density is the same in all of the multiple second waveguides 105. The width W ２ The sum of the width W of the first waveguide 104 １ If it is smaller, the current density in each second waveguide 105 will be larger than the current density in the first waveguide 104. Note that the third waveguide 107 of Modification 1 may be interposed between the first waveguide 104 and the second waveguide 105.

[0050] In the waveguide 101B, for example, the electron spin wave S can be branched into multiple waves by propagating the electron spin wave S from the first waveguide 104 toward the second waveguide 105. Furthermore, the wavelength of each branched electron spin wave S can be made longer than the wavelength of the electron spin wave S before branching.

[0051] Furthermore, in the waveguide 101B, for example, multiple electron spin waves S can be merged by propagating the electron spin waves S from the second waveguide 105 toward the first waveguide 104. Furthermore, the wavelength of the merged electron spin waves S can be made shorter than the wavelengths of the individual electron spin waves S before being merged.

[0052] As described above, the wavelength conversion device 100 of the electron spin wave of this embodiment is configured to generate a composite effective magnetic field resulting from two spin-orbit interactions within the waveguide, and the electron spins within the waveguide precess with the direction of this composite effective magnetic field as the axial direction.

[0053] Since the waveguide is formed by connecting a first waveguide and a second waveguide with different widths, when a current flows between both ends, the current density differs between the first waveguide and the second waveguide, and the electron drift velocity also differs accordingly. In the presence of the above-mentioned composite effective magnetic field, there is a proportional relationship shown in the above-mentioned formula (1) between the electron drift velocity and the wavelength of the electron spin wave.

[0054] By utilizing these relationships, the electron spin wave wavelength conversion device 100 can convert the wavelength of the electron spin wave propagating through the waveguide. For example, when an electron spin wave in a wider waveguide (first waveguide 104) is propagated to a narrower waveguide (second waveguide 105), the wavelength of the electron spin wave is converted to be longer. Conversely, when an electron spin wave in a narrower waveguide is propagated to a wider waveguide, the wavelength of the electron spin wave is converted to be shorter.

[0055] A computing device equipped with the electron spin wave wavelength conversion device 100 can process huge amounts of information by assigning a different wavelength to each information carrier, and can perform parallel computing using multiple information carriers simultaneously, for example.

[0056] Second Embodiment An electron spin wave wavelength converter according to a second embodiment of the present invention differs from the electron spin wave wavelength converter of the first embodiment in the method of confining electrons propagating in the waveguide. The electron spin wave wavelength converter of this embodiment is provided with a heterojunction between two different compound semiconductor layers, and a waveguide that propagates electron spins in the X direction along the interface (heterointerface) of the heterojunction. The other configurations are the same as those of the electron spin wave wavelength converter of the first embodiment. In this case, the shape of the potential well that confines electrons in the Z direction is triangular rather than rectangular, but the same effects as those of the electron spin wave wavelength converter of the first embodiment can be achieved.

[0057] In the second embodiment, the first barrier layer and the second barrier layer are made of different materials. For example, if one of the first barrier layer and the second barrier layer is made of InAs, the other may be made of GaAs. In this case, a waveguide is formed in the region of the heterojunction interface on the InAs side, which has a smaller energy gap than GaAs.

[0058] There are no particular limitations on the thickness of the first and second barrier layers, but from the viewpoint of miniaturization, it is preferable to select a total thickness of 250 nm or less.

[0059] The effects of the present invention will be more clearly understood from the following examples. Note that the present invention is not limited to the following examples and can be practiced with appropriate modifications within the scope of the present invention.

[0060] We fabricated a waveguide consisting of three sections of different widths, with a relatively thick section, a thin section, and another thick section connected in that order. Figure 9 shows the change in wavelength of the electron spin wave of electrons propagating through this waveguide. The wavelength is short in the thick section and long in the thin section. It is thought that the short-wavelength electron spin wave propagating through the thick section and the long-wavelength electron spin wave propagating through the thin section overlap, causing the phase of the electron spin wave to invert at the connecting section.

[0061] Figure 10 shows images of simulation results that confirm this inversion. The upper image shows the phase of an electron spin wave propagating through a waveguide with a constant thickness. The lower image shows the phase of an electron spin wave propagating through a waveguide consisting of three sections of different thicknesses, as shown in Figure 9. The upper and lower sides are colored differently at the position of the dashed line indicating the connecting section. These results confirm that the phase of the electron spin wave is inverted at the connecting section where the waveguide thickness changes.

[0062] As described above, by using a wavelength conversion device for electron spin waves, phase modulation of electron spin waves becomes possible, and a phase modulation device for electron spin waves can be obtained.

[0063] 100: Electron spin wave wavelength conversion device 101, 101A, 101B: Waveguide 102: First barrier layer 103: Second barrier layer 104: First waveguide 105: Second waveguide 106c, 106d: Electrodes 107: Third waveguide W: Width of waveguide W １ ...Width of the first waveguide W ２ ...Width of second waveguide W ３ ...Width of the third waveguide S...Electron spin wave S １ ...Electron spin wave S in the first waveguide ２ ...electron spin wave in the second waveguide λ...wavelength of the electron spin wave λ １ ...wavelength λ of electron spin waves in the first waveguide ２ ...Wavelength of electron spin wave in second waveguide

Claims

1. An electron spin wave wavelength conversion device comprising: a waveguide made of a compound semiconductor that propagates electron spins in an X direction; a first barrier layer arranged on one side of the waveguide in a Z direction that intersects with the X direction; and a second barrier layer arranged on the other side of the waveguide; the waveguide comprises a first waveguide connected to a second waveguide; the width of the second waveguide in a Y direction that intersects with the X and Z directions is narrower than the width of the first waveguide; and the materials forming the first and second barrier layers have a larger band gap energy than the material forming the waveguide.

2. The wavelength conversion device of electron spin waves described in claim 1, characterized in that one of the first barrier layer and the second barrier layer is made of AlGaAs and the other is made of AlAs, the material forming the waveguide is GaAs, and the thickness of the waveguide in the Z direction is 50 nm or less.

3. The wavelength conversion device of electron spin waves described in claim 1, characterized in that the material of the first barrier layer and the second barrier layer is AlGaAs, the material forming the waveguide is GaAs, and the thickness of the waveguide in the Z direction is 50 nm or less.

4. The wavelength conversion device of electron spin waves described in claim 1, characterized in that the material of the first barrier layer and the second barrier layer is GaAs, the material of the waveguide is InAs, and the thickness of the waveguide in the Z direction is 50 nm or less.

5. An electron spin wave wavelength conversion device as described in claim 1, characterized in that the thickness of the first barrier layer and the second barrier layer in the Z direction is 10 nm or more and 100 nm or less, and the thickness of the waveguide is 5 nm or more and 50 nm or less.

6. An electron spin wave wavelength conversion device comprising: a waveguide formed by heterojunction of two different compound semiconductor layers, which propagates electron spins in the X direction along the interface of the heterojunction; a first barrier layer disposed on one side of the waveguide in the Z direction intersecting with the X direction; and a second barrier layer disposed on the other side of the waveguide, wherein the waveguide connects a first waveguide and a second waveguide; and wherein, at the interface of the heterojunction, the width of the second waveguide is narrower than the width of the first waveguide in the Y direction intersecting with the X direction.

7. An electron spin wave wavelength conversion device as described in claim 6, characterized in that one of the first barrier layer and the second barrier layer is made of InAs and the other is made of GaAs, and at least the region of the heterojunction interface made of InAs becomes the waveguide.

8. An electron spin wave wavelength conversion device as described in claim 1 or 6, characterized in that the first waveguide and the second waveguide are connected via a third waveguide, one end of the third waveguide is connected to the first waveguide and the other end is connected to the second waveguide, and the width in the Y direction changes continuously from the one end to the other end.

9. The electron spin wave wavelength conversion device according to claim 1 or 6, characterized in that the compound semiconductor is a III-V group semiconductor.

10. An electron spin wave wavelength conversion device according to claim 1 or 6, characterized in that a plurality of second waveguides are connected to the first waveguide.

11. A computing device comprising the electron spin wave wavelength conversion device according to claim 1 or 6.

12. An electron spin wave phase modulation device comprising the electron spin wave wavelength conversion device according to claim 1 or 6.

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