System and method for determining electronic structure of tellurene based on improved tb model

Abstract

Embodiments of the present application disclose a system, method, electronic device and medium for determining electronic structure of tellurene based on an improved TB model, comprising: obtaining a target energy band structure of tellurene based on DFT-HSE; constructing an improved TB model, wherein the improved TB model comprises non-orthogonal orbitals; optimizing TB parameters based on the target energy band structure through non-orthogonal orbitals, and determining the electronic structure of the tellurene based on the optimized TB parameters. The method for determining the electronic structure of the tellurene based on the improved TB model solves the problem that the electronic structure of the tellurene cannot be accurately described in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of computer, in particular to a system and method for determining electronic structure of tellurene based on improved TB model, electronic equipment and medium. BACKGROUND

[0002] In recent years, two-dimensional materials often exhibit better properties than bulk materials due to the decrease in crystal dimension and the change in symmetry. Compared with most two-dimensional materials, tellurene has many excellent characteristics, and has great potential in the application of electronic devices such as photodetectors, field effect transistors, piezoelectric devices, modulators and captors. Therefore, it is a promising candidate material for the research of next-generation electronic devices. Therefore, it is very important to accurately describe the electronic structure of tellurene.

[0003] Due to the complex properties of multi-layer tellurene and its important application in new devices, the electronic structure of tellurene needs to be processed more reliably, more accurately and more atomically. The commonly used ab initio model has high calculation cost, and it is usually difficult to process for actual device structures with a large number of atoms.

[0004] Therefore, a method for accurately describing the electronic structure of tellurene is needed. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide a system and method for determining the electronic structure of tellurene based on an improved TB model, electronic equipment and medium, to solve the problem that the electronic structure of tellurene cannot be accurately described in the prior art.

[0006] To achieve the above purpose, the embodiments of the present application provide a method for determining the electronic structure of tellurene based on an improved TB model, which specifically comprises:

[0007] obtaining a target energy band structure of tellurene based on DFT-HSE;

[0008] constructing an improved TB model, wherein the improved TB model includes a non-orthogonal orbital;

[0009] optimizing TB parameters based on the target energy band structure through a non-orthogonal orbital, and determining the electronic structure of the tellurene based on the optimized TB parameters.

[0010] On the basis of the above technical solution, the present application can also be improved as follows:

[0011] Further, the method for obtaining the target energy band structure of tellurene based on DFT-HSE comprises:

[0012] constructing a periodic atomic structure of the tellurene;

[0013] optimizing the atomic structure;

[0014] performing a static self-consistent calculation on the optimized atomic structure to obtain a static self-consistent calculation result;

[0015] obtaining a target energy band structure of tellurene based on the static self-consistent calculation result.

[0016] Further, the non-orthogonal orbit is a non-orthogonal spds2 orbit, and the spds2 orbit includes an atomic orbital basis group of s, p, d and s* orbits.

[0017] Further, the optimization of the TB parameter based on the target energy band structure includes:

[0018] setting a first TB parameter;

[0019] calculating a first energy band corresponding to the TB parameter;

[0020] comparing the first energy band with a target energy band to calculate a first difference value between the first energy band and the target energy band;

[0021] setting a second TB parameter;

[0022] calculating a second energy band corresponding to the second TB parameter;

[0023] comparing the second energy band with the target energy band to calculate a second difference value between the second energy band and the target energy band;

[0024] calculating a difference value between the first difference value and the second difference value;

[0025] determining whether the difference value is less than a convergence value, and when the difference value is less than the convergence value, completing the optimization; and when the difference value is greater than the convergence value, re-generating the TB parameter and performing a convergence comparison with a previous TB parameter.

[0026] Further, the determination of the tellurene electronic structure based on the optimized TB parameter includes:

[0027] constructing an atomic structure composed of elements corresponding to the TB parameter;

[0028] generating a Hamiltonian of the system based on the TB parameter and the atomic structure.

[0029] Further, the determination of the tellurene electronic structure based on the optimized TB parameter includes:

[0030] when the system is a periodic system, determining an energy band of the tellurene based on the optimized TB parameter.

[0031] Further, the determining the tellurene electronic structure based on the optimized TB parameters comprises: when the system is a molecular system, determining an energy level distribution of the tellurene based on the optimized TB parameters.

[0032] A system for determining a tellurene electronic structure based on an improved TB model, comprising:

[0033] An obtaining module configured to obtain a target energy band structure of the tellurene based on DFT-HSE;

[0034] A constructing module configured to construct an improved TB model, wherein the improved TB model comprises non-orthogonal orbitals;

[0035] The improved TB model is configured to optimize TB parameters based on the target energy band structure through non-orthogonal orbitals, and determine the tellurene electronic structure based on the optimized TB parameters.

[0036] An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the method when executing the computer program.

[0037] A non-transitory computer readable medium having a computer program stored thereon, wherein the computer program is executable by a processor to implement the steps of the method.

[0038] The embodiments of the present application have the following advantages:

[0039] In the method for determining a tellurene electronic structure based on an improved TB model, a target energy band structure of the tellurene is obtained based on DFT-HSE, an improved TB model is constructed, wherein the improved TB model comprises non-orthogonal orbitals, TB parameters are optimized based on the target energy band structure through non-orthogonal orbitals, and the tellurene electronic structure is determined based on the optimized TB parameters, thereby solving the problem that the tellurene electronic structure cannot be accurately described in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other embodiments can be obtained from the provided drawings without creative labor.

[0041] The structures, proportions, sizes, etc. shown in the specification are only used to cooperate with the content disclosed in the specification for understanding and reading by those skilled in the art, and are not used to limit the conditions that can be implemented by the application, so they do not have technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the application, should still fall within the scope covered by the disclosed technology.

[0042] Figure 1 Flowchart of the method for determining the electronic structure of tellurene based on the improved TB model of the application;

[0043] Figure 2 Architecture diagram of the system for determining the electronic structure of tellurene based on the improved TB model of the application;

[0044] Figure 3 Schematic diagram of the band gap energy obtained from the DFT-HSE and the improved TB model of the application.

[0045] Figure 4 Schematic diagram of the optimized TB parameters of the application.

[0046] Figure 5 Schematic diagram of the physical structure of the electronic device provided by the application.

[0047] The reference signs are:

[0048] The acquisition module 10, the construction module 20, the improved TB model 30, the electronic device 40, the processor 401, the memory 402, and the bus 403. DETAILED DESCRIPTION

[0049] The embodiments of the application are described below by specific examples, and those skilled in the art can easily understand other advantages and effects of the application from the disclosed content. Obviously, the described examples are part of the examples of the application, not all. Based on the examples in the application, all other examples obtained by those skilled in the art without creative labor fall within the scope of the application.

[0050] EMBODIMENT

[0051] Figure 1 Flowchart of the method for determining the electronic structure of tellurene based on the improved TB model of the application, as shown in Figure 1 The method for determining the electronic structure of tellurene based on the improved TB model of the embodiment of the application includes the following steps:

[0052] S101, obtaining the target energy band structure of tellurene based on DFT-HSE;

[0053] Specifically, a periodic atomic structure of the tellurene is constructed; and the atomic structure is optimized.

[0054] A static self-consistent calculation is performed on the optimized atomic structure to obtain a static self-consistent calculation result; and a target energy band structure of the tellurene is obtained based on the static self-consistent calculation result.

[0055] DFT-HSE: density functional theory based on Heyd-Scuseria-Ernzerhof (HSE) hybrid functional.

[0056] There are three kinds of layered structures of two-dimensional tellurene, namely, α phase (α-Te) similar to 1T-molybdenum disulfide phase, β phase (β-Te) of tetragonal structure, and γ phase (γ-Te) similar to 2H-molybdenum disulfide phase, among which the α phase and the β phase exhibit semiconductor properties, and the γ phase exhibits metallic properties, which can realize different electronic functions. When the bulk phase Te structure or direction is truncated into a thin film of correct thickness, β-Te is the most stable structure in the structure relaxation limit of single-layer. The α-Te phase and the β-Te phase have nearly direct and direct band gaps, respectively, thereby enhancing the light absorption performance. Theoretical studies have shown that certain structures such as square tellurium exhibit topological insulating properties and have nontrivial edge states. Experimental studies have confirmed that two-dimensional α-Te has topological insulating properties. First-principle calculations have also shown that two-dimensional tellurene is an excellent high-temperature thermoelectric material with high room-temperature Seebeck coefficient and anisotropic lattice thermal conductivity. In addition, quantum Hall effect can be observed in a small number of layers of two-dimensional tellurene flakes under high magnetic field.

[0057] All DFT-HSE calculations are performed using the projected augmented wave (PAW) pseudopotential plane wave method, which is implemented in the VASP software package. The Brillouin zone is sampled using the Monkhorst-Pack scheme, and a 10x10x1 k-point grid is used for two-dimensional (2D) structures. The plane wave expansion kinetic energy cutoff is set to 500 eV, and the energy minimum is set to 10 -7 eV for subsequent steps. The total energy calculation uses the Gaussian expansion method with an expansion width of 0.05 eV. The total Hellmann-Feynman force in the primitive cell is reduced to for structure optimization. Ten k-points centered at the Γ point are used in the primitive cell.

[0058] To avoid the interaction between adjacent layers, the calculation is performed in a vacuum space of .

[0059] Figure 3 Figure showing the band gap energies obtained from DFT-HSE and the improved TB model. The fifth column shows the deviation between the HSE and TB values. The experimental data are shown in the sixth column, and all energies are in eV.

[0060] S102, constructing an improved TB model, wherein the improved TB model comprises non-orthogonal orbitals;

[0061] Specifically, the non-orthogonal orbitals are non-orthogonal spds2 orbitals, and the spds2 orbitals comprise an atomic orbital basis group of s, p, d and s* orbitals.

[0062] The spds2 orbitals comprise near-neighbor interactions and spin-orbit coupling, which accurately determine the electronic structure of the alpha, beta and gamma phases of tellurium. Using this non-orthogonal spds2 orbital basis group, the number of parameters of the TB model can be increased, and the effect of theoretical fitting and optimization will be better, i.e., the difference with the target energy band will be smaller.

[0063] A reliable and accurate target band structure is a major requirement for tight-binding modeling success. In order to calculate the target energy band structure, a screened HSE hybrid functional is used based on the density functional theory (DFT) theory. HSE can accurately calculate the band gap of a semiconductor and reasonable effective mass. The calculated energy band structure of tellurium from the self-consistent DFT-HSE is very consistent with existing experimental data and is well compared with other theoretical researches.

[0064] In the improved TB model, a non-orthogonal basis is used, and a spds2 orbital set considering three near-neighbor interactions. The effect of spin-orbit coupling is considered through a split energy term. Through the built-in automation process of nanoskif, a set of 88 parameters is optimized, and the root mean square deviation of fitting is within 12 meV.

[0065] The optimized TB parameters are shown in Figure 4 . It is worth noting that this set of TB parameters can produce accurate band structures of all three different forms of tellurium. The energies of the three structures of tellurium around the VBM and CBM are consistent.

[0066] The comparison of the band gaps obtained by the DFT-HSE model and the improved TB model is shown in Figure 3 . For the band gap energy, the fitting accuracy is less than 1.2%. For the effective mass, in most cases, the deviation between DFT-HSE and TB values is less than 10%, which is acceptable.

[0067] S103, optimizing TB parameters based on the target energy band structure through non-orthogonal orbitals, and determining the electronic structure of tellurium based on the optimized TB parameters;

[0068] Specifically, the TB parameters only exist between any two atoms with interaction, and the TB parameters do not correspond to a specific atomic structure, but contain the interaction information between the atoms. Assuming that a structure is composed of atoms of A, B and C elements, if A-B, A-C and B-C have interactions, then the Hamiltonian of any structure composed of A, B and C elements can be constructed by using the corresponding set of TB parameters. Further, if a periodic system is constructed, the band structure can be obtained from the Hamiltonian.

[0069] setting a first TB parameter; calculating a first band corresponding to the TB parameter;

[0070] comparing the first band with a target band, calculating a first difference value between the first band and the target band; setting a second TB parameter; calculating a second band corresponding to the second TB parameter;

[0071] comparing the second band with the target band, calculating a second difference value between the second band and the target band; calculating a difference value between the first difference value and the second difference value;

[0072] determining whether the difference value is less than a convergence value, when the difference value is less than the convergence value, completing the optimization; when the difference value is greater than the convergence value, re-generating the TB parameter and comparing it with the previous TB parameter for convergence.

[0073] constructing an atomic structure composed of elements corresponding to the TB parameter; generating a Hamiltonian of the system based on the TB parameter and the atomic structure. When the system is a periodic system, determining the band of the tellurium monolayer based on the optimized TB parameter, and when the system is a molecular system, determining the energy level of the tellurium monolayer based on the optimized TB parameter.

[0074] A general improved TB model is established for accurate calculation of the electronic structure of tellurium monolayer. The improved TB model is based on the Slater-Koster method. In order to optimize the TB parameters, the screened hybrid DFT method is used to obtain the accurate target band structure. The accuracy of the improved TB model is verified by comparing the band gap of different transitions, the effective mass of different band edges and the ab initio band structure. One of the main features of the improved TB model is that only one set of parameters is needed to reproduce the band structure of tellurium monolayer with different structural configurations. Our tight-binding model can be easily extended to other TMDC materials with similar electronic properties to tellurium monolayer. The improved TB model established in this paper is of great significance for simulating quantum transport in nanoelectronic devices based on TMDC materials.

[0075] This method for determining the electronic structure of tellurene based on an improved TB model obtains the target band structure of tellurene using DFT-HSE; constructs an improved TB model, which includes non-orthogonal orbitals; optimizes the TB parameters based on the target band structure using non-orthogonal orbitals; and determines the electronic structure of tellurene based on the optimized TB parameters. This method solves the problem of existing technologies being unable to accurately describe the electronic structure of tellurene.

[0076] Figure 2 This is a flowchart of a system embodiment of the present invention for determining the electronic structure of tellurene based on the improved TB model 30; as shown. Figure 2 As shown, an embodiment of the present invention provides a system for determining the electronic structure of tellurene based on an improved TB model 30, comprising the following steps:

[0077] The acquisition module 10 is used to obtain the target band structure of tellurene based on DFT-HSE; construct the periodic atomic structure of the tellurene; optimize the atomic structure; perform static self-consistent calculation on the optimized atomic structure to obtain the static self-consistent calculation result; and obtain the target band structure of tellurene based on the static self-consistent calculation result.

[0078] Module 20 is used to construct an improved TB model 30, wherein the improved TB model 30 includes non-orthogonal orbitals; the non-orthogonal orbitals are non-orthogonal spds2 orbitals, and the spds2 orbitals include atomic orbital basis sets of s, p, d and s* orbitals.

[0079] An improved TB model 30 is used to optimize TB parameters based on the target band structure using non-orthogonal orbitals, and to determine the tellurene electronic structure based on the optimized TB parameters. The process includes: setting a first TB parameter; calculating a first band corresponding to the TB parameter; comparing the first band with the target band and calculating a first difference value between the two bands; setting a second TB parameter; calculating a second band corresponding to the second TB parameter; comparing the second band with the target band and calculating a second difference value between the two bands; calculating the difference between the first and second difference values; determining whether the difference is less than a convergence value; if the difference is less than the convergence value, optimization is complete; if the difference is greater than the convergence value, the TB parameters are regenerated and compared with the previous TB parameters for convergence.

[0080] Construct an atomic structure with elements corresponding to the TB parameters; generate the Hamiltonian of this system based on the TB parameters and the atomic structure. When the system is a periodic system, determine the energy band of the tellurene based on the optimized TB parameters. When the system is a molecular system, determine the energy level distribution of the tellurene based on the optimized TB parameters.

[0081] The system for determining the electronic structure of tellurene based on the improved TB model 30 comprises the following steps: obtaining the target energy band structure of tellurene based on DFT-HSE by the obtaining module 10; constructing the improved TB model 30 by the constructing module 20, wherein the improved TB model 30 comprises non-orthogonal orbits; optimizing the TB parameters based on the target energy band structure by the non-orthogonal orbits by the improved TB model 30, and determining the electronic structure of the tellurene based on the optimized TB parameters. The method for determining the electronic structure of tellurene based on the improved TB model 30 solves the problem that the electronic structure of tellurene cannot be accurately described in the prior art.

[0082] Figure 5 An electronic device entity structure schematic diagram provided by an embodiment of the present application is shown in FIG. 1. Figure 5 As shown in FIG. 1, the electronic device 40 comprises a processor 401, a memory 402 and a bus 403.

[0083] The processor 401 and the memory 402 can communicate with each other through the bus 403.

[0084] The processor 401 is configured to invoke the program instructions in the memory 402 to execute the method provided by each method embodiment described above, for example, comprising: obtaining the target energy band structure of tellurene based on DFT-HSE; constructing the improved TB model 30, wherein the improved TB model 30 comprises non-orthogonal orbits; optimizing the TB parameters based on the target energy band structure by the non-orthogonal orbits, and determining the electronic structure of the tellurene based on the optimized TB parameters.

[0085] The present embodiment provides a non-transitory computer readable medium, which stores computer instructions, and the computer instructions make the computer execute the method provided by each method embodiment described above, for example, comprising: obtaining the target energy band structure of tellurene based on DFT-HSE; constructing the improved TB model, wherein the improved TB model comprises non-orthogonal orbits; optimizing the TB parameters based on the target energy band structure by the non-orthogonal orbits, and determining the electronic structure of the tellurene based on the optimized TB parameters.

[0086] Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware, and the foregoing program can be stored in a computer readable medium, and the program executes the steps of the method embodiments when executed.

[0087] The device embodiments described above are merely illustrative, wherein the units illustrated as separate components can or can not be physically separate, and the components illustrated as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the modules can be selected to achieve the purposes of the embodiments according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0088] Through the description of the above embodiments, those skilled in the art can clearly understand that the embodiments can be realized by means of software plus necessary general hardware platforms, and of course can also be realized by hardware. Based on such understanding, the above technical solutions, essentially or in other words, the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer readable medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods of the embodiments or some parts of the embodiments.

[0089] Although the present application has been fully described by way of examples with reference to the accompanying drawings, it is apparent that various modifications and changes can be made thereto without departing from the spirit of the application. Therefore, the present application should not be limited to the embodiments described herein, but should be given the widest scope in accordance with the principles and novel features disclosed herein.

Claims

1. A method for determining the electronic structure of tellurene based on an improved TB model, characterized in that, The method specifically includes: The target band structure of tellurene was obtained based on DFT-HSE. Construct an improved TB model, wherein the improved TB model includes non-orthogonal trajectories; Based on the target band structure, the TB parameters are optimized via non-orthogonal orbits, including: Set the first TB parameter; Calculate the first energy band corresponding to the TB parameter; The first energy band is compared with the target energy band, and the first difference value between the first energy band and the target energy band is calculated; Set the second TB parameter; Calculate the second energy band corresponding to the second TB parameter; The second energy band is compared with the target energy band, and a second difference value between the second energy band and the target energy band is calculated; Calculate the difference between the first difference value and the second difference value; Determine whether the difference is less than the convergence value. If the difference is less than the convergence value, the optimization is completed. If the difference is greater than the convergence value, regenerate the TB parameters and compare them with the previous TB parameters for convergence. The electronic structure of tellurene was determined based on the optimized TB parameters.

2. The method for determining the electronic structure of tellurene based on the improved TB model according to claim 1, characterized in that, The method for obtaining the target band structure of tellurene based on DFT-HSE includes: Construct the periodic atomic structure of the tellurene; The atomic structure is optimized; Static self-consistent calculations were performed on the optimized atomic structure to obtain the static self-consistent calculation results; The target band structure of tellurene was obtained based on the static self-consistent calculation results.

3. The method for determining the electronic structure of tellurene based on the improved TB model according to claim 1, characterized in that, The non-orthogonal orbitals are non-orthogonal spds2 orbitals, which include atomic orbital basis sets of s, p, d, and s* orbitals.

4. The method for determining the electronic structure of tellurene based on the improved TB model according to claim 1, characterized in that, Determining the tellurene electronic structure based on the optimized TB parameters includes: Construct atomic structures composed of elements corresponding to TB parameters; The Hamiltonian of this system is generated based on the TB parameters and the atomic structure.

5. The method for determining the electronic structure of tellurene based on the improved TB model according to claim 4, characterized in that, Determining the tellurene electronic structure based on the optimized TB parameters includes: When the system is a periodic system, the band structure of the tellurene is determined based on the optimized TB parameters.

6. The method for determining the electronic structure of tellurene based on the improved TB model according to claim 4, characterized in that, Determining the tellurene electronic structure based on the optimized TB parameters includes: When the system is a molecular system, the energy level distribution of the tellurene is determined based on the optimized TB parameters.

7. A system for determining the electronic structure of tellurene based on an improved TB model, characterized in that, include: The acquisition module is used to obtain the target band structure of tellurene based on DFT-HSE; A building module for constructing an improved TB model, wherein the improved TB model includes non-orthogonal orbits; An improved TB model is used to optimize TB parameters based on the target band structure using non-orthogonal orbitals, and the electronic structure of the tellurene is determined based on the optimized TB parameters. The improved TB model is also used for: Set the first TB parameter; Calculate the first energy band corresponding to the TB parameter; The first energy band is compared with the target energy band, and the first difference value between the first energy band and the target energy band is calculated; Set the second TB parameter; Calculate the second energy band corresponding to the second TB parameter; The second energy band is compared with the target energy band, and the second difference value between the second energy band and the target energy band is calculated; Calculate the difference between the first difference value and the second difference value; Determine whether the difference is less than the convergence value. If the difference is less than the convergence value, the optimization is completed. If the difference is greater than the convergence value, regenerate the TB parameters and compare them with the previous TB parameters for convergence.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 6.

9. A non-transitory computer-readable medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 6.

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