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

Abstract

The present invention provides an electron spin wave wavelength conversion device that enables easy and accurate control of the wavelength of electron spin waves, and a computing device equipped therewith. [Solution] The electron spin wave wavelength conversion device 100 of the present invention is made of a compound semiconductor and comprises a waveguide 101 that propagates electron spin in the X direction, a first barrier layer 102 arranged on one side of the waveguide 101 in the Z direction intersecting the X direction, and a second barrier layer 103 arranged on the other side of the waveguide 101. The waveguide 101 is formed by connecting a first waveguide 104 and a second waveguide 105, and in the Y direction intersecting the X and Z directions, the width W2 of the second waveguide 105 is narrower than the width W1 of the first waveguide 104, and the first barrier layer 102 and the second barrier layer 103 have a larger bandgap energy than the waveguide 101.

Description

[Technical Field]

[0001] The present invention relates to a wavelength conversion device, a computing device, and a phase modulation device for electron spin waves. [Background technology]

[0002] The spatial patterns drawn by electron spin polarization are known to be usable as information carriers with wave properties called electron spin waves (Non-Patent Literature 1). The present inventors have developed a technique for optically observing electron spin waves, and the use of electron spin waves in various materials, including semiconductors, is expected. Since the wavelength of an electron spin wave is a continuously changing parameter, a vast amount of information can be processed by assigning a different wavelength to each information carrier, enabling, for example, parallel computing using multiple information carriers simultaneously. In this case, a technique is needed to easily and accurately control the wavelength of the assigned electron spin wave, but such a technique has not yet been established. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Y. Kunihashi et al., Nat. Commun. 7, 10722 (2016). [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The present invention has been made in view of the above circumstances, and aims to provide an electron spin wave wavelength conversion device, a computing device equipped therewith, and an electron spin wave phase modulation device that enable easy and accurate control of the wavelength of an electron spin wave. [Means for solving the problem]

[0005] 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 is made of a compound semiconductor and comprises a waveguide for propagating electron spin in the X direction, a first barrier layer disposed on one side of the waveguide in the Z direction intersecting the X direction, and a second barrier layer disposed on the other side of the waveguide, wherein the waveguide is formed by connecting the first waveguide and the second waveguide, the width of the second waveguide is narrower than the width of the first waveguide in the Y direction intersecting the X direction and the Z direction, and the materials forming the first barrier layer and the second barrier layer have a larger bandgap energy than the material forming the waveguide.

[0007] (2) In the electron spin wave wavelength conversion apparatus described in (1) above, it is preferable that one of the first barrier layer and the second barrier layer is made of AlGaAs, the other is made of AlAs, the waveguide material 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 apparatus described in (1) above, it is preferable 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.

[0009] (4) In the electron spin wave wavelength conversion apparatus described in (1) above, it is preferable that the material of the first barrier layer and the second barrier layer is GaAs, the material forming 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 apparatus 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 relates to an electron spin wave wavelength converter comprising: a waveguide formed by a heterojunction between two layers of different compound semiconductors, which propagates electron spin 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 the X direction; and a second barrier layer disposed on the other side of the waveguide, wherein the waveguide is formed by connecting the first waveguide and the second waveguide, and at the interface of the heterojunction, the width of the second waveguide in the Y direction intersecting the X direction is narrower than the width of the first waveguide.

[0012] (7) In the electron spin wave wavelength conversion apparatus 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 interface of the heterojunction made of InAs becomes the waveguide.

[0013] (8) In the electron spin wave wavelength conversion apparatus described in any of (1) to (7) above, the first waveguide and the second waveguide are connected via a third waveguide, and 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 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 semiconductor.

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

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

[0017] (12) The phase modulation device for electron spin waves according to one aspect of the present invention includes the wavelength conversion device for electron spin waves described in any one of (1) to (10) above.

Effects of the Invention

[0018] According to the present invention, it is possible to provide a wavelength conversion device for electron spin waves that can easily and accurately control the wavelength of electron spin waves, an arithmetic device including the same, and a phase modulation device for electron spin waves.

Brief Description of the Drawings

[0019] [Figure 1] (a) A perspective view of the wavelength conversion device for electron spin waves according to the first embodiment of the present invention. (b) A perspective view of the waveguide constituting the wavelength conversion device for electron spin waves in (a). [Figure 2] A diagram schematically showing an example of the crystal structure of a compound semiconductor constituting a waveguide. [Figure 3] A diagram showing a plan view of the wavelength conversion device for electron spin waves from the Y direction (left diagram) and a distribution diagram of the band gap energy of electrons in the Z direction within the wavelength conversion device for electron spin waves (right diagram). [Figure 4] (a) A diagram schematically showing the effective magnetic field generated by an electric field due to the crystal structure of a waveguide. (b) A diagram schematically showing the effective magnetic field generated by an electric field due to the energy band structure in the Z direction. (c) A diagram schematically showing the combined effective magnetic field obtained by combining the effective magnetic fields in (a) and (b). [Figure 5] A diagram for explaining an electron spin wave propagating through a waveguide. [Figure 6] A graph for explaining the relationship between the drift velocity of electrons and the wavelength of electron spin waves. [Figure 7] A diagram showing a plan view of the waveguide of Modification 1 from the Z direction. [Figure 8] A diagram showing a plan view of the waveguide of Modification 2 from the Z direction. [Figure 9]This diagram shows the change in wavelength of electron spin waves propagating through a waveguide in a waveguide consisting of three sections of different widths, with the relatively wide section, narrow section, and wide section connected in that order. [Figure 10] This figure shows the simulation results of the example. [Modes for carrying out the invention]

[0020] Hereinafter, an electron spin wave wavelength conversion device and a computing device according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings. Note that, for the sake of clarity, the drawings used in the following description may show enlarged versions of key features, and the dimensional ratios of each component may not be the same as those in reality. Furthermore, the materials, dimensions, etc., exemplified in the following description are merely examples, and the present invention is not limited to them. It can be implemented with appropriate modifications without altering the essence of the invention.

[0021] <First Embodiment> Figure 1(a) is a perspective view of an electron spin wave wavelength conversion device 100 according to a first embodiment of the present invention. The electron spin wave wavelength conversion device 100 mainly comprises 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 intersecting (preferably perpendicular to) the X direction (here, the Z direction), the first barrier layer 102 is arranged on one side (here, the upper side) of the waveguide 101, and the second barrier layer 103 is arranged on the other side (here, the lower side) of the waveguide 101.

[0022] Figure 1(b) is a perspective view of waveguide 101. Waveguide 101 is formed by connecting a first waveguide 104 and a second waveguide 105, both extending in one direction (here, the X direction). The end of the first waveguide 104 and the end of the second waveguide 105 in the X direction are connected. The first waveguide 104 and the second waveguide 105 may be separate entities, but it is preferable that they be integrated from the viewpoint of not hindering the propagation of electron spin waves.

[0023] In the Y direction, which intersects (preferably orthogonal to) the X and Z directions, the first waveguide 104 and the second waveguide 105 have different widths W. Here, we illustrate the case where the width W2 of the second waveguide is narrower than the width W1 of the first waveguide.

[0024] The thickness T of the waveguide 101 in the Z direction is almost uniform throughout. Furthermore, the thickness T is only necessary if the material forming the waveguide is thick enough 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, even more preferably 10 nm or less, and may be 5 nm or more. If the thickness T is within this range, the motion of the propagating electrons can be restricted to almost within the XY plane. If it is thicker than 50 nm, it approaches the properties of a bulk material, and may not solve the problem of the present invention.

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

[0026] Figure 2 schematically shows an example of the crystal structure of a compound semiconductor constituting waveguide 101. Here, the case where the compound semiconductor is GaAs is illustrated. GaAs has a zincblende-type crystal structure as shown in Figure 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, thus breaking the overall symmetry of the crystal field. In a compound semiconductor where the crystal field symmetry is broken in this way, an electric field E1 is generated in a specific direction overall.

[0027] Waveguide 101 is sandwiched in the Z direction between a first barrier layer 102 and a second barrier layer 103. The first barrier layer 102 is joined to one main surface 101a of the waveguide extending in the XY plane, and the second barrier layer 103 is joined to the other main surface 101b opposite to the first main surface 101a. The shape of the first barrier layer 102 only needs to be such that it covers at least one main surface 101a of the waveguide. The shape of the second barrier layer 103 only needs to be such that it covers at least the other main surface 101b of the waveguide.

[0028] The materials of the first barrier layer 102 and the second barrier layer 103 may be different or the same, and have a larger bandgap energy than the compound semiconductor constituting 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 may be AlGaAs, and the other may be AlAs or AlGaAs. Also, for example, if the waveguide 101 is made of InAs, the materials of the first barrier layer 102 and the second barrier layer 103 may be selected from, for example, InP, AlAs, and GaAs.

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

[0030] Figure 3 shows a plan view of the electron spin wave wavelength converter 100 from the Y direction (left figure) and a distribution diagram of the electron bandgap energy in the Z direction within the electron spin wave wavelength converter 100 (right figure). The bandgap energies of the first barrier layer 102 and the second barrier layer 103 act as energy barriers, causing the electron wavefunction to be almost localized within the waveguide 101, and restricting the electron's motion region to within the waveguide 101. An electric field E2 is generated from the layer with the relatively smaller bandgap energy towards the layer with the larger bandgap energy.

[0031] Figure 4(a) schematically shows the effective magnetic field H1 generated in momentum space by the electric field E1 originating from the crystal structure of waveguide 101. The effective magnetic field H1 is generated in complexly tilted directions at each position in the crystal structure, influenced by the motion of electrons flowing within waveguide 101, and acts on the rotation of electron spin waves. This effect is called the Dresselhaus spin-orbit interaction.

[0032] Figure 4(b) schematically shows the effective magnetic field H2 generated in momentum space by the electric field E2 resulting from the energy band structure (quantum well structure) in the Z direction of the waveguide. The effective magnetic field H2 is generated in a counterclockwise direction around the electric field E2 in the Z direction and acts on the rotation of the electron spin wave. This effect is called the Rashba spin-orbit interaction.

[0033] Figure 4(c) schematically shows the combined effective magnetic field H (=H1+H2) obtained by combining two effective magnetic fields H1 and H2. When the effective magnetic fields H1 and H2 are combined, the combined effective magnetic field H is tilted in a specific direction, as shown in Figure 4(c). The electron spins in waveguide 101 undergo precession with the direction of the combined effective magnetic field H as their axis.

[0034] Figure 5 illustrates the electron spin wave S propagating in the X direction in a waveguide 101 that constitutes the electron spin wave wavelength conversion device 100. The first barrier layer 102 and the second barrier layer 103 are not shown in this figure. Electrodes 106c and 106d are connected to both ends 101c and 101d of the waveguide 101, respectively, and a voltage V is applied between the ends of the waveguide 101 via electrodes 106c and 106d to generate an electric field. Each electron in the waveguide 101 moves under the influence of this electric field, and the electron spin of each electron undergoes precession with the direction of the effective magnetic field H as its axis. As a result, the distribution of electron spin orientations propagates in the direction of the electric field as an electron spin wave S.

[0035] The wavelength λ of the electron spin wave S differs when it propagates within the first waveguide 104 and when it propagates within the second waveguide 105. That is, when the electron spin wave S propagates from the first waveguide 104 to the second waveguide 105, the wavelength λ2 of the electron spin wave S2 propagating within the second waveguide 105 is longer than the wavelength λ1 of the electron spin wave S1 propagating within the first waveguide 104. Conversely, when the electron spin wave S propagates from the second waveguide 105 to the first waveguide 104, the wavelength λ1 of the electron spin wave S1 propagating within the first waveguide 104 is shorter than the wavelength λ2 of the electron spin wave S2 propagating within the second waveguide 105.

[0036] If the ratio (W2 / W1) is less than 0.1, more electrons will collide with the sidewalls of waveguide 101A, making it difficult to suppress electron scattering due to the resistance from the sidewalls. Also, if the ratio (W2 / W1) is greater than 0.9, the difference between the widths W1 and W2 becomes smaller, reducing the wavelength conversion effect.

[0037] This section explains the effect of the waveguide width W on the wavelength λ of the electron spin wave S. The wavelength λ of the electron spin wave is given by equation (1) below. Equation (1) contains h / (2π), m, α, β1, β3, V drift , V Fermi These represent the following physical quantities, respectively. h / (2π): Reduced Planck constant (Dirac constant) m: Effective mass of electrons, α: Constant for Rashba spin-orbit interaction, β1, β3: Dresselhaus spin-orbit interaction constants.

[0038]

number

[0039] Figure 6 shows the drift velocity V of an electron moving under the influence of an electric field. drift This is a graph illustrating the relationship between the wavelength λ of electron spin waves and the graph. The horizontal axis of the graph represents the Fermi velocity V. Fermi Drift speed V drift The ratio (Vdrift / V Fermi ) shows. The vertical axis of the graph indicates the wavelength λ of the electron spin wave. In the graph of FIG. 6, in the above equation (1), m is 0.067m0 (m0 is the rest mass of a free electron), α is -1.75×10 -13 (eVm), β1 is 1.70×10 -13 (eVm), β3 is 0.41×10 -13 (eVm), and the curve when the wavelength λ of the electron spin wave is a function of the drift velocity V drift of the electrons is drawn.

[0040] The drift velocity V drift is given by the following equation (2). j, e, and n S included in equation (2) respectively represent the following physical quantities. j: Current density, e: Elementary charge, n S : Carrier density.

[0041]

Equation

[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. 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. In the first waveguide 104 with a large width W, the wavelength λ1 of the electron spin wave becomes shorter, and conversely, in the first waveguide 104 with a small width W, the wavelength λ2 of the electron spin wave becomes longer.

[0043] A modification example 1 regarding the configuration of the waveguide 101 is shown. FIG. 7 is a plan view of the waveguide 101A of the modification example 1 viewed from the Z direction. In the waveguide 101A, the first waveguide 104 and the second waveguide 105 are connected via the third waveguide 107. The configuration except for the interposition of the third waveguide 107 is the same as that of the waveguide 101.

[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 width W3 in the Y direction changes continuously from one end 107a to the other end 107b of the third waveguide 107. Here, we illustrate the case where the width W3 decreases continuously and linearly with respect to the distance from the first waveguide 104 or the second waveguide 105 from one end 107a to the other end 107b.

[0045] Furthermore, although this example illustrates the case where the width W3 of one end 107a matches the width W1 of the first waveguide 104, the width W3 of one end 107a may be smaller than the width W1. Similarly, although this example illustrates the case where the width W3 of the other end 107b matches the width W2 of the second waveguide 105, the width W3 of the other end 107b may be larger than the width W2.

[0046] Furthermore, although this example illustrates the case where both sides 107c and 107d of the third waveguide 107 in the Y direction are planar, both sides 107c and 107d may be curved surfaces that are convex inward or convex outward, as shown by the dashed lines. In other words, the width W3 may change nonlinearly with respect to the distance from the first waveguide 104 or the second waveguide 105.

[0047] In waveguide 101A, the presence of a third waveguide 107 with a continuously changing width makes the change in width W between the first waveguide 104 and the second waveguide 105 gradual. Therefore, at the connection point between the first waveguide 104 and the second waveguide 105, the resistance that electrons experience from the sidewalls of waveguide 101A is reduced, and electron scattering at the sidewalls can be suppressed.

[0048] A modified example 2 of the waveguide 101 configuration is shown. Figure 8 is a plan view of waveguide 101B of modified example 2 from the Z direction. In waveguide 101B, multiple second waveguides 105 are connected to one first waveguide 104. Here, the case where the number of connected second waveguides 105 is 2 is shown as an example, but it may be 3 or more. The configuration other than the number of connected second waveguides 105 is the same as the configuration of waveguide 101.

[0049] The width W2 of each second waveguide 105 can be set individually so that the electron spin S is converted to a desired wavelength, and may be the same or different from each other. The configuration of waveguide 101B is the same as when the second waveguide 105 in waveguide 101 is divided into multiple parts, and the current density is the same in each of the multiple second waveguides 105. If the sum of the widths W2 of all second waveguides 105 is smaller than the width W1 of the first waveguide 104, the current density in each second waveguide 105 will be greater than the current density in the first waveguide 104. In addition, a third waveguide 107, as in Modification 1, may be interposed between the first waveguide 104 and the second waveguide 105.

[0050] In waveguide 101B, for example, by propagating the electron spin wave S from the first waveguide 104 toward the second waveguide 105, the electron spin wave S can be split into multiple waves. 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 waveguide 101B, multiple electron spin waves S can be merged by, for example, propagating an electron spin wave S from the second waveguide 105 toward the first waveguide 104. In addition, the wavelength of the merged electron spin wave S can be made shorter than the wavelengths of each electron spin wave S before merging.

[0052] As described above, the electron spin wave wavelength conversion device 100 of this embodiment is configured to generate a combined effective magnetic field in the waveguide due to the interaction of two spin orbits, and for the electron spins in the waveguide to precess with the direction of this combined 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 current flows between the two ends, the current density differs between the first waveguide and the second waveguide, and consequently, the electron drift velocity also differs. In the presence of the above combined effective magnetic field, there is a proportional relationship between the electron drift velocity and the wavelength of the electron spin wave, as shown in equation (1) above.

[0054] By utilizing these relationships, the electron spin wave wavelength converter 100 can convert the wavelength of electron spin waves propagating through the waveguides. For example, when propagating electron spin waves from the wider waveguide (first waveguide 104) to the narrower waveguide (second waveguide 105), the wavelength of the electron spin waves is converted to be longer. Conversely, when propagating electron spin waves from the narrower waveguide to the wider waveguide, the wavelength of the electron spin waves is converted to be shorter.

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

[0056] <Second Embodiment> The electron spin wave wavelength conversion device according to the second embodiment of the present invention differs from the electron spin wave wavelength conversion device of the first embodiment in terms of the method for confining electrons propagating through the waveguide. The electron spin wave wavelength conversion device of this embodiment has a heterojunction between two layers of different compound semiconductors, and is equipped with a waveguide that propagates electron spin 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 conversion device of the first embodiment. In this case, the shape of the potential well that confines electrons in the Z direction is triangular instead of rectangular, but it can achieve the same effect as the electron spin wave wavelength conversion device of the first embodiment.

[0057] In the second embodiment, the materials of the first barrier layer and the second barrier layer are different. For example, if one of the first and second barrier layers is InAs, the other can be GaAs. In this case, at the interface of the heterojunction, a waveguide is formed in the InAs region where the energy gap is smaller than that of GaAs.

[0058] The thicknesses of the first and second barrier layers are not particularly limited, but from the viewpoint of miniaturization, it is preferable to select a total thickness of 250 nm or less. [Examples]

[0059] The effects of the present invention will be further clarified by the following examples. However, the present invention is not limited to the following examples and can be implemented with appropriate modifications without altering its essence.

[0060] A waveguide was fabricated consisting of three sections of different widths, with the relatively wide section, narrow section, and wide section connected in sequence. Figure 9 shows the change in wavelength of electron spin waves propagating through this waveguide. The wavelength is shorter in the wide section and longer in the narrow section. It is thought that the phase of the electron spin waves at the connected section is reversed due to the overlap of short-wavelength electron spin waves propagating in the wide section and long-wavelength electron spin waves propagating in the narrow section.

[0061] Figure 10 shows simulation results confirming this inversion. The upper image shows the phase of an electron spin wave propagating through a waveguide of constant width. The lower image shows the phase of an electron spin wave propagating through a waveguide consisting of three sections of different widths, as shown in Figure 9. At the position of the dashed line indicating the connection point, the colors of the upper and lower images are different. From this result, it can be confirmed that the phase of the electron spin wave inverts at the connection point where the waveguide width changes.

[0062] As described above, by using an electron spin wave wavelength conversion device, it is possible to perform phase modulation of electron spin waves, thereby creating an electron spin wave phase modulation device. [Explanation of Symbols]

[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...electrode 107...Third waveguide W...Wavelength of the waveguide W1...Width of the first waveguide W2...Width of the second waveguide W3...Width of the third waveguide S...Electron spin wave S1... Electron spin wave in the first waveguide S2... Electron spin wave in the second waveguide λ···Wavelength of electron spin wave λ1...Wavelength of electron spin wave in the first waveguide λ2...Wavelength of electron spin wave in the second waveguide

Claims

1. It consists of a compound semiconductor and a waveguide that propagates electron spin in the X direction, In the Z direction intersecting the X direction, the waveguide comprises a first barrier layer positioned on one side and a second barrier layer positioned on the other side of the waveguide. The waveguide is formed by connecting the first waveguide and the second waveguide. In the Y direction intersecting the X direction and the Z direction, the width of the second waveguide is narrower than the width of the first waveguide. An electron spin wave wavelength conversion device characterized in that the materials forming the first barrier layer and the second barrier layer have a bandgap energy greater than the material forming the waveguide.

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

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

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

5. The electron spin wave wavelength conversion apparatus according to 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. The device comprises a waveguide formed by a heterojunction between two layers of different compound semiconductors, which propagates electron spin in the X direction along the interface of the heterojunction, a first barrier layer positioned on one side of the waveguide in the Z direction intersecting the X direction, and a second barrier layer positioned on the other side of the waveguide. The waveguide is formed by connecting the first waveguide and the second waveguide. An electron spin wave wavelength conversion device characterized in that, at the interface of the heterojunction, the width of the second waveguide in the Y direction intersecting the X direction is narrower than the width of the first waveguide.

7. The electron spin wave wavelength conversion device according to 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 interface of the heterojunction made of InAs becomes the waveguide.

8. The first waveguide and the second waveguide are connected via a third waveguide. The electron spin wave wavelength conversion apparatus according to claim 1 or 6, characterized in that the third waveguide has one end connected to the first waveguide and the other end connected to the second waveguide, and its 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 group III-V semiconductor.

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

11. A computing device characterized by comprising an electron spin wave wavelength conversion device as described in claim 1 or 6.

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

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