Spin heat transport double-layer van der waal nanoribbon device, design method and application

Abstract

This invention relates to the field of nanoelectronics, addressing the technical problem that the asymmetry of the JGNR band structure inhibits spin-driven thermoelectric transport processes. Specifically, it relates to a spin-thermal transport bilayer van der Waals nanoribbon device, its design method, and applications. Starting with a single-layer JGNR, and based on the relative arrangement of carbon atoms in the upper and lower layers, a BJGNR van der Waals heterostructure with various interlayer stacking configurations is constructed. A bilayer JGNR van der Waals structure with an AB1 interlayer stacking configuration is selected to construct the bilayer van der Waals nanoribbon device. This invention selectively enhances the transmission probability of the spin-up conduction channel, and the increase in the spin-up channel current directly leads to an increase in the overall spin current. This effect is stably exhibited over a wide temperature range, significantly improving the spin-thermal transport performance of the device.

Description

Technical Field

[0001] This invention relates to the field of nanoelectronics, and more particularly to a spin thermal transport bilayer van der Waals nanoribbon device, its design method, and its application. Background Technology

[0002] The evolution of spintronics is primarily driven by the gradual understanding of the electron spin degree of freedom, coupled with the synergistic progress in semiconductor physics, magnetic functional materials, and micro / nano fabrication technologies. A series of fundamental discoveries, exemplified by the giant magnetoresistance (GMR) effect, have enabled spintronics to rapidly penetrate the fields of high-density data storage and logic operations, exhibiting significant advantages such as low joule power consumption, ultra-high recording density, and high-speed information processing. Common spin devices, such as spin valve structures, magnetic tunnel junctions (MTJs), and spin filter layers, have found extensive practical applications in magnetic storage units, sensing elements, and quantum computing platforms.

[0003] The fabrication of single-atom-thick graphene sheets using a mechanical exfoliation strategy has not only ushered in a new era in the study of two-dimensional atomic crystals but also provided a novel platform for constructing spintronic devices. Due to its extremely high carrier mobility and extended spin lifetime, graphene has been rapidly recognized as a superior candidate medium for conducting spin signals. Subsequently, two-dimensional systems such as transition metal dichalcogenides (TMDCs) and hexagonal boron nitrides (h-BN) have emerged, greatly expanding the physical mechanisms of spin modulation based on dimensional constraints and laying the material science foundation for designing low-dimensional devices such as spin-modulated field-effect transistors and spin-driven light-emitting diodes. In recent years, the discovery of intrinsic two-dimensional magnets such as CrI3 and Fe3GeTe3 has made the controllable regulation of spin-ordered states near room temperature increasingly a reality, thus providing a new path for the development of next-generation spin memory cells and logic modules.

[0004] Against this technological backdrop, exploring spintronics schemes using two-dimensional materials as basic building blocks is considered a key breakthrough for achieving high-performance, low-dissipation spin information processing technology. Nevertheless, achieving efficient thermoelectric conversion still faces significant material limitations. On the one hand, the types of materials are very limited, and the thermoelectric conversion coefficients vary greatly between different systems; on the other hand, many candidate materials exhibit a rapid performance degradation trend at higher operating temperatures, severely hindering their practical application. More importantly, achieving efficient thermoelectric conversion is typically highly sensitive to operating temperature. This nonlinear thermo-spin coupling behavior makes it difficult to guarantee the output stability and reproducibility of devices across different temperature ranges. Therefore, it is urgent to achieve stable and controllable spin thermal transport performance over a wide temperature range through sophisticated material structure design and interface engineering methods.

[0005] In existing technologies, a universal preparation strategy for JGNR ferromagnetic graphene nanoribbons with two different edge configurations involves asymmetrically embedding a topological defect lattice composed of benzene ring structural units into one serrated edge while maintaining the original intact morphology of the opposite serrated edge. This disrupts the structural mirror symmetry of the system and induces an unbalanced distribution of sublattice sites within each unit cell, ultimately triggering spontaneous breaking of spin symmetry. In this system, there exists an optimal lattice spacing for the defect lattice, which completely suppresses the magnetic edge states at the modified edge. Furthermore, the electronic properties of the defect-modified ferromagnetic graphene nanoribbons (JGNRs) differ significantly from those of conventional serrated graphene nanoribbons (zGNRs). Specifically, the spin-up and spin-down branch channels in the band structure exhibit significant differences at the Fermi level (…). The distribution is asymmetrical in the vicinity of ), located in The left and right sides. This band asymmetry inhibits the spin-driven thermoelectric transport process, making it difficult for the device to achieve the ideal spin thermoelectric conversion efficiency. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a spin-thermal transport bilayer van der Waals nanoribbon device, its design method, and its application, solving the technical problem that the asymmetry of the JGNR band structure inhibits the spin-driven thermo-electric transport process.

[0007] To address the aforementioned technical problems, this invention provides the following technical solution: a design method for a spin-thermal transport bilayer van der Waals nanoribbon device, comprising the following steps: Starting with a single-layer JGNR as the initial structure, and based on the difference in the relative arrangement of carbon atoms in the upper and lower layers, a BJGNR van der Waals heterostructure with multiple interlayer stacking configurations was constructed. A bilayer JGNR van der Waals structure with an interlayer stacking configuration of AB1 was selected from the BJGNR van der Waals heterostructure to construct a bilayer van der Waals nanoribbon device for characterizing its quantum state downlink transport behavior. The bilayer van der Waals nanoribbon device includes a central scattering region and semi-infinite electrodes connected to its left and right sides respectively, with the carrier migration direction set to Z-axis orientation. When external control is applied to the AB1 configuration, the temperature difference between the two infinitely long electrodes on the left and right sides is used to drive spin-related charge carriers to pass through the central scattering region to form a spin current output, thereby selectively enhancing the transmission probability of the spin-up conduction channel.

[0008] Furthermore, the interlayer stacking method of the AB1 configuration is as follows: The three carbon atoms in any six-membered ring in the lower layer correspond to the ring center position of the adjacent six-membered ring in the upper layer. At the same time, the defects in both the upper and lower layers are concentrated on a common edge side of this bilayer JGNR van der Waals structure.

[0009] Furthermore, the BJGNR van der Waals heterostructure also includes AA2 and AB2 configurations, with the following interlayer stacking methods: AA2 configuration: All atomic positions in the upper layer are perfectly perpendicular to those in the lower layer, and the defects in the upper and lower layers are located at the two opposite edges of this bilayer JGNR van der Waals structure; AB2 configuration: The three carbon atoms in any six-membered ring in the lower layer correspond to the ring center position of the adjacent six-membered ring in the upper layer, and the defects in the upper and lower layers are located at two different edges of this bilayer JGNR van der Waals structure.

[0010] Furthermore, the process of constructing the bilayer van der Waals nanoribbon device includes: Four AB1 configuration cells after structural relaxation are selected and arranged in series to form the longitudinal dimension of the central scattering region. The semi-infinite electrode is constructed using BJGNR nanoribbons made of the same material as the central scattering region and extending infinitely in the opposite direction.

[0011] Furthermore, the central scattering region is used to suppress the mutual coupling between the left and right halves of the infinitely long electrodes and to serve as the main transport channel; The semi-infinite electrode is used to simulate the electron pool behavior of a real macroscopic electrode.

[0012] Furthermore, the single-layer JGNR specifically refers to: Using serrated graphene nanoribbons zGNR as the parent material, a periodically arranged lattice of topological defects is introduced into the serrated edge region on one side, while the original intact shape of the serrated edge on the other side is maintained.

[0013] Furthermore, the application of bilayer van der Waals nanoribbon devices in converting thermal energy into spin-polarized current includes methods for spin thermoelectric conversion using bilayer van der Waals nanoribbon devices, including: Out-of-plane compressive strain was applied along the X direction to the double-layer JGNR van der Waals structure of configuration AB1; Under zero bias conditions, the left and right semi-infinite electrodes of the bilayer van der Waals nanoribbon device are placed in different temperature environments, causing them to spin-current. The amplification enhances the spin-driven thermal transport capability of the bilayer van der Waals nanoribbon device.

[0014] Furthermore, the temperature of the left semi-infinite electrode of the bilayer van der Waals nanoribbon device... Temperature difference between two semi-infinite electrodes The applied compressive strain .

[0015] By employing the above technical solution, the present invention provides a spin thermal transport bilayer van der Waals nanoribbon device, its design method, and its application, which has at least the following beneficial effects: This invention uses a BJGNR van der Waals structure under out-of-plane compressive stress to construct a bilayer van der Waals nanoribbon device. Due to the selective control of its spin channels, this structure can effectively enhance the thermally excited spin transport process, thus providing a design basis for improving the performance of thermal spin devices based on geometry optimization.

[0016] The intrinsic AB1 configuration of the bilayer JGNR van der Waals structure exhibits bipolar magnetic semiconductor properties. The constructed bilayer van der Waals nanoribbon device maintains the original spin-resolved current properties while achieving a multiplied spin current and charge current compared to the monolayer. To address this, this invention introduces out-of-plane compressive strain for synergistic modulation. As the interlayer spacing is gradually reduced, both the band structure and transmission peak width broaden. Further employing temperature difference to drive the directional movement of spin electrons amplifies the spin current again, with the incremental portion of this spin current primarily provided by the spin-up channel. This effect has a wide applicable temperature range, effectively utilizing waste heat for thermoelectric conversion and reducing energy waste.

[0017] This invention utilizes a standard and necessary theoretical model and experimental scheme to analyze spin transport characteristics by constructing a nanoribbon device structure consisting of an interconnected left semi-infinite electrode, a central scattering region, and a right semi-infinite electrode. The configuration of the semi-infinite electrodes prevents the accumulation of spurious charges due to finite size effects. The temperature difference between the left and right semi-infinite electrodes provides a driving force for charge carriers to pass through the central scattering region, thereby forming a spin current output.

[0018] This invention employs an external control method of applying out-of-plane compressive stress, utilizing the spin-dependent carrier migration driven by temperature difference to selectively enhance the transmission probability of the spin-up conduction channel. The increase in the spin-up channel current directly leads to an increase in the overall spin current. This effect is stably manifested over a wide temperature range and can significantly improve the spin thermal transport performance of the device. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1This is a schematic diagram of the single-layer (4,2)-JGNR structure, spin density distribution, band structure, and projected density of states in Embodiment 1 of the present invention. Figure 2 The BJGNR van der Waals unit cell structure and its band structure under different stacking conditions in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the band structure and spin density distribution of the AB1 configuration BJGNR in Embodiment 1 of the present invention; Figure 4 This is a structural diagram of the bilayer van der Waals nanoribbon device constructed using the single-layer (4,2)-JGNR and AB1 configurations in Embodiment 1 of the present invention. Figure 5 This is a schematic diagram of the transmission spectrum and spin-resolved current, spin current and charge current of the monolayer (4,2)-JGNR and AB1 configurations in Embodiment 1 of the present invention. Figure 6 In Embodiment 2 of the present invention, AB1 is applied along the X-axis direction. Band structure diagram of out-of-plane strain; Figure 7 In Embodiment 2 of the present invention, AB1 is applied along the X-axis direction. Transmission spectrum of out-of-plane strain; Figure 8 In Embodiment 2 of the present invention, AB1 is applied along the X-axis direction. A schematic diagram of spin-resolved current, spin current, and charge current under out-of-plane compressive strain. Detailed Implementation

[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This will allow for a full understanding of how the present application uses technical means to solve technical problems and achieve technical effects, and to facilitate its implementation.

[0021] This invention adopts the existing (4,2)-JGNR naming for ferromagnetic graphene nanoribbons (JGNR), where the number 4 represents the number of serrated carbon chains distributed laterally, used to indicate the width of the nanoribbon; and the number 2 represents the spacing between adjacent benzene ring defects along the modified edge direction.

[0022] Example 1 This embodiment discloses a design method for a spin-thermal transport bilayer van der Waals nanoribbon device, including the following steps: S1. Based on the single-layer (4,2)-JGNR nanoribbon unit cell, and according to the difference in the relative arrangement of atoms between the upper and lower layers, a variety of stacked configurations of bilayer Janus graphene (BJGNR) van der Waals nanoribbon systems were constructed.

[0023] On one of the serrated edges, a topological defect array arranged in a periodic pattern is introduced, while the serrated edge on the opposite side maintains its original complete shape. The nomenclature system of (n,m)-JGNRs is adopted, where n represents the number of serrated carbon chains distributed laterally along the nanobelt, and m represents the center distance between adjacent benzene rings on the defect-arranged side edge. In this example, a single-layer (4,2)-JGNR nanobelt unit cell configuration is selected. The geometric structure, spin density distribution characteristics, and calculated results of band structure and projected density of states of the monolayer (4,2)-JGNR nanoribbon unit cell are presented in the following table. Figure 1 (a) to (c) are shown in the figures. The two edges of the nanoribbon are capped with hydrogen (H) atoms to saturate potential dangling bonds. A first-principles computational framework is used, employing periodic boundary conditions along the z-axis to construct the computational model. Vacuum isolation layers greater than 15 Å are placed in the x and y directions to avoid non-physical interactions between adjacent mirror layers. Structural relaxation calculations are performed using the Quantum ATK software package, combining density functional theory (DFT) and the non-equilibrium Green's function method (NEGF). During the relaxation process, the lattice constant in the z-direction remains constant until the residual force on each atom converges to below 0.01 eV / Å. The relevant computational parameters are set as follows: a 1×1×15 k-point grid is used for Brillouin zone sampling, and the plane wave cutoff energy is set to 80 Hartree. Based on these parameters, the electronic properties of the unit cell of the monolayer (4,2)-JGNR nanoribbon are analyzed.

[0024] Periodic defect modification disrupts the continuity of the serrated edge state, thereby quenching the magnetism at the defect-modified edge. Total energy calculations show that the AFM state is the ground state of the isolated monolayer (4,2)-JGNR nanoribbon unit cell. The calculation results are shown in Table 1. Figure 1 Image (b) depicts the spin density distribution of the unit cell of a monolayer (4,2)-JGNR nanoribbon, representing the spatial difference in charge density between spin-up and spin-down electrons. It is evident that the spin density is primarily concentrated in the upper edge region. Due to Janus reconstruction, one edge is essentially nonmagnetic, and the transport-related spin polarization state is mainly determined by the other edge, which remains magnetic. Given that this work focuses on spin-related transport in magnetized device states, subsequent analysis will be conducted on the FM configuration, which serves as the corresponding field-polarized transport state. Figure 1 As shown in (c), this figure illustrates the spin-resolved band structure and projected density of states (PDOS) of a monolayer (4,2)-JGNR nanoribbon unit cell in the ferromagnetic state. Near the Fermi level (…),… The conduction band minimum (CBM) of bisverse magnetic nanoribbons (zGNRs) originates from the spin-up band, while the valence band maximum (VBM) originates from the spin-down band. This constitutes a typical characteristic of bipolar magnetic semiconductor (BMS) properties, distinguishing it from the metallic zero-bandgap characteristic exhibited by traditional sawtooth graphene nanoribbons in the ferromagnetic state. Notably, at the high-symmetry Z-point, the spin-resolved band exhibits significant energy asymmetry, with the spin-up band located at the Fermi level (…). The energy level is below 0.55 eV, while the spin-down band is located at the Fermi level (…). 0.27eV or higher.

[0025] Table 1 Total energy of (4,2)-JGNR in NM, FM and AFM states. (4,2)-JGNR -4531.72763 -4531.85512 -4532.70551

[0026] Based on a single-layer (4,2)-JGNR nanoribbon unit cell, BJGNR van der Waals heterostructures with different stacking configurations were constructed by systematically controlling the interlayer atomic arrangement. Two stacking types were used in this example, denoted as AAn and ABn. In the AAn stack, the two layers are approximately vertically aligned; while in the ABn stack, the lower carbon atoms are located below vacancies in the upper lattice. The subscript n is used to distinguish the defect arrangement, where n=1 and n=2 correspond to the cases where defects are located on the same edge and opposite edges, respectively. Structural relaxation was then performed again using the Quantum ATK calculation program to converge the residual forces between atoms to below 0.01 eV / Å. Simultaneously, van der Waals interactions were introduced between the layers, described using the DFT-D3 correction scheme. Electronic property analysis was performed on the unit cells of the BJGNR van der Waals heterostructures with four different magnetic moment arrangements in the magnetic ground state.

[0027] Four different interlayer stacking configurations and their band structures are as follows: Figure 2 As shown in (a) to (d), they are denoted as AA1, AA2, AB1, and AB2 respectively, according to the above description. Figure 2 (a) shows the top and side view structures of the AA1 configuration and its band structure; it can be seen that the AA1 configuration converges to the NM ground state and the band is completely spin degenerate, which means that the AA1 configuration cannot be used to build nanodevices, and its spin characteristics will not be further described in the following.

[0028] Figure 2 (b) shows the top and side views of the AA2 configuration and its band structure; it can be seen that the AA2 configuration exhibits spin-polarized BMS properties, in which the Fermi level... The two downward-spinning flat bands intersect each other and converge at point Z in the Brillouin zone.

[0029] Figure 2 (c) shows the top and side view structures and band structure of the AB1 configuration; it can be seen that the AB1 configuration also exhibits BMS properties.

[0030] Figure 2 Image (d) shows the top and side views of the AB2 configuration and its band structure; it can be seen that the AB2 configuration exhibits metallic properties, with the bands of both spin channels crossing the Fermi level. It exhibits metallic properties.

[0031] Because the AB1 configuration exhibits more significant broadening of its spin-up and spin-down bands at point Z, it possesses greater tuning value. For these reasons, this example will focus on the AB1 configuration system.

[0032] like Figure 3 As shown in (a) in the figure, the interlayer spacing is in equilibrium. =3.39 Å. From the spin-resolved band structure of the AB1 configuration in equilibrium, it can be seen that the Fermi level... The nearby CBM is contributed by the spin-up subband, while the VBM corresponds to the spin-down subband, clearly demonstrating the typical characteristics of the BMS. The spin-up band is located at the Fermi level. At 0.34 eV below, the spin-down energy band is located at the Fermi level. At 0.27 eV above. Furthermore, the band gaps at point Z between the two bands, numbered 114 and 115 respectively (spin-up and spin-down channels), are 0.16 eV and 0.14 eV, respectively. For example... Figure 3 As shown in (b), the spin density distribution of AB1 indicates that the spin density is mainly localized near the upper edge. Given that the unit cell of a monolayer (4,2)-JGNR nanoribbon has only one edge contributing to the transport-related spin polarization state, and the magnetic moment after bilayer stacking is also localized to a single edge, and since this embodiment focuses on the spin transport behavior under the magnetized device state, the subsequent analysis will revolve around the corresponding field-polarized transport state, i.e., the FM configuration.

[0033] S2. Select a bilayer JGNR van der Waals structure with an interlayer stacking configuration of AB1 from the BJGNR van der Waals heterostructure, and construct a bilayer van der Waals nanoribbon device to characterize its quantum state-download carrier transport behavior.

[0034] The AB1-configuration bilayer JGNR van der Waals structure was selected as the basis for constructing a bilayer van der Waals nanoribbon device as a dual-probe transport model, which was used to study its carrier transport behavior in the quantum state, such as... Figure 4As shown, the bilayer van der Waals nanoribbon device comprises a central scattering region and semi-infinite electrodes connected to its left and right sides, respectively, with the carrier migration direction set to the Z-axis orientation. Regarding the central scattering region: four structurally relaxed AB1-type cells are arranged in series; this scale effectively suppresses the mutual coupling between the left and right semi-infinite electrodes and serves as the main transport channel. Regarding the semi-infinite electrodes: BJGNR nanoribbons of the same material as the central scattering region are used, extending infinitely outward to simulate the electron pool behavior of real macroscopic electrodes. For the coupling at the interface: first-principles calculations are used to optimize the contact configuration between the semi-infinite electrodes and the central scattering region, ensuring a continuous distribution of the electron wavefunction at the interface.

[0035] The transmission spectra were calculated and analyzed using the transmission coefficient formula to observe the difference in electronic transport between the AB1 configuration and the monolayer (4,2)-JGNR nanoribbon unit cell; the formula for calculating the transmission coefficient is: ; in, For spin-resolved transmission coefficients, including and These are the spin transmission coefficients for spin-up and spin-down, respectively; and These are the hysteresis and lead Green's functions of the scattering region, respectively. and These are the coupling matrices for the left and right semi-infinite electrodes, respectively.

[0036] Under zero bias conditions, by changing the temperatures of the left and right infinitely long electrodes, the left infinitely long electrode is defined as the high-temperature region (temperature is...). The right half of the infinitely long electrode is in the low-temperature region (temperature is...). This creates a temperature difference in the system. This temperature difference leads to different carrier concentrations at the two ends of the device, resulting in different Fermi-Dirac distributions at the two ends, as shown in the formula: ; in, Given the Boltzmann constant, and the Fermi-Dirac distribution determined by energy E and temperature T, the spin polarization current generated by thermal drive in the device... It can be calculated using the Landauer-Büttiker formula: ; in, Indicates electron charge; Represents Planck's constant; and These represent the Fermi-Dirac distributions of the left and right electrodes in a non-equilibrium state, respectively. denoted as the spin transmission coefficient for spin-up and spin-down directions.

[0037] Spin polarization current Including spin-up current and spin-down current Two components; through spin-polarized current Calculate spin flow and charge flow The generated spin flow is caused by Calculations show that the charge flow is from Calculated.

[0038] The transmission spectra of electronic devices constructed from monolayer (4,2)-JGNR nanoribbon units and bilayer JGNR van der Waals structures with an AB1 configuration are as follows: Figure 5 As shown in (a) and (b) in the figure, it can be seen that the transmission spectra of the above electronic devices all exhibit asymmetric characteristics that are significantly related to their respective band structures.

[0039] Nanoribbon devices constructed from monolayer (4,2)-JGNNR nanoribbon units exhibit spin polarization current. and the corresponding spin flow Charge flow The results are as follows: Figure 5 As shown in (c) and (e) in the figure; spin polarization current of the AB1 configuration bilayer van der Waals nanoribbon device. and the corresponding spin flow Charge flow The results are as follows: Figure 5 As shown in (d) and (f) in the figure.

[0040] from Figure 5 As can be seen from (b) and (d) in the figure: compared with the single-layer structure, the spin-up current and spin-down current Exhibiting opposite signs, the spin-resolved current of the bilayer structure is approximately twice that of the monolayer, thus creating a multiplied spin current. But at the same time, charge flow It is almost twice that of a single layer, and further improvements in spin heat transport performance are needed, hence the introduction of out-of-plane strain synergistic regulation.

[0041] Example 2 This embodiment describes the application of the bilayer van der Waals nanoribbon device designed in Example 1 in spin thermoelectric conversion. Electronic properties are modulated by applying out-of-plane compressive strain along the X-direction to the AB1-configured bilayer JGNR van der Waals structure.

[0042] To quantitatively describe the deviation of the interlayer spacing from the equilibrium position, compressive strain is introduced. ,in 3.39 Å equilibrium interlayer spacing. Under this definition, compressive strain Corresponding interlayer compression, compressive strain Stretch the corresponding interlayer spacing. Figure 6 (a) in the figure reflects the deviation parameter. The AB1 band structure corresponding to the band structure varying in 0.1 Å steps within the range of -0.4 Å to 0.4 Å. Overall, different compressive strains... The band structure remains similar across different strain values, indicating that the basic band structure formed by AB1 exhibits strong robustness to external strain. However, the band structure shows a clear and consistent dependence on the magnitude and direction of strain: when compressive strain... When the interlayer coupling is enhanced, the band dispersion increases, leading to a gradual broadening of the band; conversely, when the compressive strain is reduced, the band dispersion decreases. At this time, interlayer interactions weaken, and the energy band gradually narrows. Of particular note is the phenomenon at maximum compressive strain. At -0.4 Å, the band gaps of bands 114 and 115 at point Z in the Brillouin zone significantly increase, reaching 0.35 eV and 0.28 eV respectively, far exceeding the equilibrium values. This band gap tuning effect provides the electronic structure basis for subsequent improvements in thermal spin transport performance.

[0043] To investigate the modulating effect of out-of-plane strain on the thermal spin transport properties of the AB1 configuration, this embodiment focuses only on out-of-plane compressive strain ( The modulation of thermal spin transport in the AB1 configuration can significantly alter band dispersion and enhance transmission characteristics. Since the AB1 configuration exhibits spin-resolved transport characteristics closely related to its band structure under different interlayer spacings, a series of compressive strains were selected. Based on the structure with negative values, corresponding dual-probe devices were constructed to systematically investigate their quantum transport behavior and thermal spin response characteristics. Each device consists of a central scattering region and connected left and right semi-infinite electrodes. Figure 7 This reflects the corresponding spin-resolved transmission spectrum. For example... Figure 7 As shown, the spin-up and spin-down transmission peaks are located at the Fermi level, respectively. On both sides, this energy separation allows charge carriers with different spin polarizations to pass through the Fermi level separately. Transport occurs through the upper and lower energy channels. With increasing out-of-plane compressive strain, the spin-polarized bands systematically shift towards higher energies. At point Z in the Brillouin zone, the band widths of both channels significantly increase, and these evolutionary characteristics are clearly reflected in the transmission spectrum. When the out-of-plane compressive strain increases from... During the process of increasing from 0 Å to -0.4 Å, the transmission peaks of the two spin channels synchronously shift towards the Fermi level. Movement, such as Figure 6 As shown. Especially in At -0.4 Å, the spin-down channel exhibits the widest transmission peak, which helps to narrow the difference between the spin-up and spin-down channels, thereby significantly improving the spin thermal transport performance of the system.

[0044] Figure 8 In the diagram, (a)-(e) and (f)-(j) respectively reflect the continuous application of the AB1 configuration along the X-axis direction. = 0 Å to -0.4% Å compressive strain, the spin polarization current obtained by the constructed nanoribbon electronic device and the corresponding spin flow Charge flow With temperature The changing pattern; from Figure 8 From (a)-(e) and (f)-(j), it can be seen that the thermally driven current of the device exhibits consistent behavior: as temperature... Increased temperature or temperature difference leads to spin-up current. With spin-down current Both increase monotonically, and their signs are always opposite, which helps to obtain a larger spin flow. .

[0045] At temperature Under the condition of [condition], in the spin-resolved current of the equilibrium device, 68.3 Å, spin flow With charge flow 117.14 Å and 19.47 Å respectively; compressed to out-of-plane strain. After = -0.4Å, spin-up current Increased to 91.6A (an increase of approximately 34.1%), while the spin-down current... Almost unchanged, spin flow Increased to 138.27A, charge flow The spin current increased to 44.97 A, with a maximum increase of approximately 18.1%. This demonstrates a significant enhancement in the spin-resolved current driven by the temperature gradient, with a substantial increase in the current contribution of the spin-up channel, while the spin-down channel remained almost unaffected. Total spin current. The net increase mainly comes from spin-up current. The improvement. Despite the charge flow While there was an increase, this increase was primarily due to contributions from the spin-up channel, indicating that out-of-plane strain has a more sensitive preferential modulation capability for the spin channel. In summary, the appropriate application of out-of-plane compressive strain enhances the transmission and thermal excitation of the spin channel, thereby achieving spin flow. The enhancement optimized the thermal spin performance of the device.

[0046] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0047] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Since the above embodiments are fundamentally similar to the method embodiments, their descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0048] The above embodiments provide a detailed description of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A design method for a spin-thermal transport bilayer van der Waals nanoribbon device, characterized in that, The method includes the following steps: Starting with a single-layer JGNR as the initial structure, and based on the difference in the relative arrangement of carbon atoms in the upper and lower layers, a BJGNR van der Waals heterostructure with multiple interlayer stacking configurations was constructed. A bilayer JGNR van der Waals structure with an interlayer stacking configuration of AB1 was selected from the BJGNR van der Waals heterostructure to construct a bilayer van der Waals nanoribbon device for characterizing its quantum state downlink transport behavior. The bilayer van der Waals nanoribbon device includes a central scattering region and semi-infinite electrodes connected to its left and right sides respectively, with the carrier migration direction set to Z-axis orientation. When external control is applied to the AB1 configuration, the temperature difference between the two infinitely long electrodes on the left and right sides is used to drive spin-related charge carriers to pass through the central scattering region to form a spin current output, thereby selectively enhancing the transmission probability of the spin-up conduction channel.

2. The design method for a double-layer van der Waals nanoribbon device according to claim 1, characterized in that, The interlayer stacking method of the AB1 configuration is as follows: The three carbon atoms in any six-membered ring in the lower layer correspond to the ring center position of the adjacent six-membered ring in the upper layer. At the same time, the defects in both the upper and lower layers are concentrated on a common edge side of this bilayer JGNR van der Waals structure.

3. The design method for a double-layer van der Waals nanoribbon device according to claim 1, characterized in that, The BJGNR van der Waals heterostructure also includes AA2 and AB2 configurations, with the following interlayer stacking methods: AA2 configuration: All atomic positions in the upper layer are perfectly perpendicular to those in the lower layer, and the defects in the upper and lower layers are located at the two opposite edges of this bilayer JGNR van der Waals structure; AB2 configuration: The three carbon atoms in any six-membered ring in the lower layer correspond to the ring center position of the adjacent six-membered ring in the upper layer, and the defects in the upper and lower layers are located at two different edges of this bilayer JGNR van der Waals structure.

4. The design method for a double-layer van der Waals nanoribbon device according to claim 1, characterized in that, The process of constructing the bilayer van der Waals nanoribbon device includes: Four AB1 configuration cells after structural relaxation are selected and arranged in series to form the longitudinal dimension of the central scattering region. The semi-infinite electrode is constructed using BJGNR nanoribbons made of the same material as the central scattering region and extending infinitely in the opposite direction.

5. The design method for a double-layer van der Waals nanoribbon device according to claim 4, characterized in that, The central scattering region is used to suppress the mutual coupling between the left and right halves of the infinitely long electrodes and serves as the main transport channel; The semi-infinite electrode is used to simulate the electron pool behavior of a real macroscopic electrode.

6. The design method for a double-layer van der Waals nanoribbon device according to claim 1, characterized in that, The single-layer JGNR specifically refers to: Using serrated graphene nanoribbons zGNR as the parent material, a periodically arranged lattice of topological defects is introduced into the serrated edge region on one side, while the original intact shape of the serrated edge on the other side is maintained.

7. A spin-thermal transport bilayer van der Waals nanoribbon device, characterized in that, The device was fabricated using the design method of any one of claims 1 to 6.

8. The application of the bilayer van der Waals nanoribbon device as described in claim 7 in converting thermal energy into spin-polarized current.

9. A method for spin thermoelectric conversion using the bilayer van der Waals nanoribbon device as described in claim 7, characterized in that, include: Out-of-plane compressive strain was applied along the X direction to the double-layer JGNR van der Waals structure of configuration AB1; Under zero bias conditions, the left and right semi-infinite electrodes of the bilayer van der Waals nanoribbon device are placed in different temperature environments, causing them to spin-current. The amplification enhances the spin-driven thermal transport capability of the bilayer van der Waals nanoribbon device.

10. The method according to claim 9, characterized in that, The temperature of the left semi-infinite electrode of the bilayer van der Waals nanoribbon device Temperature difference between two semi-infinite electrodes The applied compressive strain .

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