CN111883218B - Method and device for regulating nonlinear optical properties of transition metal sulfide - Google Patents

Abstract

The application provides a method and a device for regulating and controlling nonlinear optical properties of transition metal sulfide, wherein the method comprises the following steps: replacing one atom in the transition metal sulfide structure with a calibration atom to obtain a new atom lattice; optimizing the lattice parameter of the new atomic lattice to obtain the optimized lattice parameter; sequentially performing self-consistent calculation and non-self-consistent calculation according to the optimized lattice parameter to obtain a preprocessed lattice parameter, and determining an electronic band gap according to the preprocessed lattice parameter; non-self-consistent calculation is carried out according to the preprocessed lattice parameters, a wave function is obtained, GW-BSE calculation is carried out according to the wave function, and an optical band gap is obtained; determining a bandgap difference from the optical bandgap and the electronic bandgap, determining a correction parameter from the bandgap difference; and simulating according to the correction parameters and the control parameters to obtain a plurality of second-order nonlinear non-zero response spectrums. According to the technical scheme, the nonlinear optical property of the transition metal sulfide is improved, and the complexity of the calculation simulation process is reduced.

Description

A method and device for regulating the nonlinear optical properties of transition metal sulfides

Technical Field

The present invention relates to the field of analog computing technology, and in particular to a method and device for regulating the nonlinear optical properties of transition metal sulfides.

Background technique

Two-dimensional materials have become a hot research topic in the field of materials in recent years because of their atomic-level thickness and excellent material properties. Among them, transition metal sulfides are widely used in the manufacture of photocatalysts, infrared photodetectors, nonlinear optical information processing devices, light-emitting diodes and other components because of their high integrability, optical band gap and exciton effect. In transition metal sulfides, the electron Coulomb screening effect will weaken as the distance of the electron in the non-periodic direction increases, making transition metal sulfides highly tunable.

On the one hand, due to the broken in-plane centrosymmetry of transition metal sulfides, among which the H-phase transition metal sulfides have broken in-plane centroinversion symmetry, transition metal sulfides have even-order nonlinear responses. Due to the existence of out-of-plane symmetry, the out-of-plane even-order nonlinear optical response is zero, which reduces the nonlinear optical properties of transition metal sulfides. On the other hand, methods such as DFT (Densityfunctional theory) based on PBE (Perdew-Burke-Ernzerhof, exchange-correlation functional) are currently often used to calculate and simulate the optical properties of transition metal sulfides. However, the existing calculation simulation methods are relatively complicated and require a large amount of calculation when calculating the band gap and band gap difference of transition metal sulfides.

Summary of the invention

The problem solved by the invention is how to improve the nonlinear optical properties of transition metal sulfides and reduce the complexity of calculating the band gap.

In order to solve the above problems, the present invention provides a method and device for regulating the nonlinear optical properties of transition metal sulfides.

In a first aspect, the present invention provides a method for regulating the nonlinear optical properties of transition metal sulfides, comprising:

Replace one atom in the transition metal sulfide structure with a calibration atom to obtain a new atomic lattice.

The lattice parameters of the new atomic lattice are optimized to obtain optimized lattice parameters.

Self-consistent calculation and non-self-consistent calculation are sequentially performed according to the optimized lattice parameters to obtain the pre-processed lattice parameters, and the electronic band gap is determined according to the pre-processed lattice parameters.

A non-self-consistent calculation is performed based on the pre-processed lattice parameters to obtain a wave function, and a GW-BSE (perturbation theory of multi-body Green's function-Bethe-Salpeter equation) calculation is performed based on the wave function to obtain an optical band gap.

A band gap difference is determined based on the optical band gap and the electronic band gap, and a correction parameter is determined based on the band gap difference.

A simulation is performed according to the correction parameters and the preset control parameters to obtain a plurality of second-order nonlinear non-zero response spectra of the transition metal sulfide.

In a second aspect, the present invention provides a device for regulating the nonlinear optical properties of transition metal sulfides, comprising:

The replacement module is used to replace an atom in the transition metal sulfide structure with a calibration atom to obtain a new atomic lattice.

The optimization module is used to optimize the lattice parameters of the new atomic lattice to obtain optimized lattice parameters.

The first processing module is used to perform self-consistent calculation and non-self-consistent calculation in sequence according to the optimized lattice to obtain the pre-processed lattice parameters, and determine the electronic band gap according to the pre-processed lattice parameters.

The second processing module is used to perform non-self-consistent calculation according to the pre-processed lattice parameters to obtain a wave function, and perform GW-BSE calculation according to the wave function to obtain an optical band gap.

A correction module is used to determine a band gap difference according to the optical band gap and the electronic band gap, and to determine a correction parameter according to the band gap difference.

The simulation module is used to perform simulation according to the correction parameters and preset control parameters to obtain multiple second-order nonlinear non-zero response spectra of the transition metal sulfide.

In a third aspect, the present invention provides a device for regulating the nonlinear optical properties of transition metal sulfides, comprising a memory and a processor.

The memory is used to store computer programs.

The processor is used to implement the method for regulating the nonlinear optical properties of transition metal sulfides as described above when executing the computer program.

In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for regulating the nonlinear optical properties of transition metal sulfides as described above is implemented.

The beneficial effects of the method and device for regulating the nonlinear optical properties of transition metal sulfides of the present invention are as follows: by simulating the method of replacing atoms in simulation software, an intrinsic dipole can be introduced into the structure of transition metal sulfides, breaking the out-of-plane symmetry of the structure, thereby improving the second-order nonlinear optical properties of transition metal sulfides. By drawing the energy band diagram of the lattice, the electronic band gap of the transition metal sulfide is determined, and then the optical band gap of the transition metal sulfide is calculated using the GW-BSE method. It is not necessary to consider whether the absorption edges of the excited electron interactions are aligned, which can simplify the process of calculating the optical band gap and increase the speed of determining the band gap difference. The technical solution of the present application improves the linear optical properties of transition metal sulfides by introducing an intrinsic dipole, and uses the GW-BSE method to calculate the optical band gap, which simplifies the process of determining the band gap difference and reduces the complexity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic flow chart of a method for regulating the nonlinear optical properties of transition metal sulfides according to an embodiment of the present invention;

FIG2 is a front view of a MoSSe lattice according to an embodiment of the present invention;

FIG3 is a left side view of a MoSSe lattice according to an embodiment of the present invention;

FIG4 is a top view of a MoSSe lattice according to an embodiment of the present invention;

FIG5 is an energy band diagram of a MoSSe lattice according to an embodiment of the present invention;

FIG6 is an electronic absorption spectrum and an exciton absorption spectrum of the MoSSe lattice after the electronic band gap is shifted to the optical band gap in an embodiment of the present invention;

FIG7 is a second-order nonlinear response spectrum of all non-zero components of the MoSSe lattice according to an embodiment of the present invention;

FIG8 is a device for regulating the nonlinear optical properties of transition metal sulfides according to an embodiment of the present invention.

Detailed ways

In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. "Multiple" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In the embodiments of the present application, _MoS2 is used as an example to describe in detail the method for regulating the nonlinear optical properties of transition metal sulfides.

As shown in FIG1 , a method for regulating the nonlinear optical properties of transition metal sulfides provided in an embodiment of the present invention comprises the following steps:

100, an atom in the transition metal sulfide structure is replaced by a calibration atom to obtain a new atomic lattice.

Specifically, taking _MoS2 as an example, one S atom in the hexagonal lattice H phase _MoS2 is replaced by a Se atom to construct a three-atom MoSSe lattice. The MoSSe lattice is shown in Figures 2, 3 and 4.

200, optimizing the lattice parameters of the new atomic lattice to obtain optimized lattice parameters.

300 , performing self-consistent calculation and non-self-consistent calculation in sequence according to the optimized lattice parameters to obtain pre-processed lattice parameters, and determining the electronic band gap according to the pre-processed lattice parameters.

Specifically, the electronic band gap includes a direct band gap and an indirect band gap.

400, performing a non-self-consistent calculation based on the preprocessed lattice parameters to obtain a wave function, and performing a GW-BSE (perturbation theory of many-body Green's function-Bethe-Salpeter equation) calculation based on the wave function to obtain an optical band gap.

500, determining a band gap difference according to the optical band gap and the electronic band gap, and determining a correction parameter according to the band gap difference.

600 , performing simulation according to the correction parameters and preset control parameters to obtain a plurality of second-order nonlinear non-zero response spectra of the transition metal sulfide.

In this embodiment, by simulating the method of replacing atoms in the simulation software, an intrinsic dipole can be introduced into the transition metal sulfide structure, breaking the out-of-plane symmetry of the structure, thereby improving the second-order nonlinear optical properties of the transition metal sulfide. By drawing the energy band diagram of the lattice, the electronic band gap of the transition metal sulfide is determined, and then the optical band gap of the transition metal sulfide is calculated using the GW-BSE method. It is not necessary to consider whether the absorption edges of the excited electron interaction are aligned, which can simplify the process of calculating the optical band gap and increase the speed of determining the band gap difference. The technical solution of the present application improves the linear optical properties of the transition metal sulfide by introducing an intrinsic dipole, and uses the GW-BSE method to calculate the optical band gap, which simplifies the process of determining the band gap difference and reduces the complexity.

Preferably, optimizing the lattice parameters of the new atomic lattice to obtain the optimized lattice parameters comprises:

The lattice parameters of the new atomic lattice are optimized by using VASP software, and the lattice parameter simulation results when the energy of the new atomic lattice is at the lowest point are determined by simulation, and the optimized lattice parameters are determined according to the lattice parameter simulation results, wherein when the energy of the new atomic lattice is at the lowest point, a and c are the unit cell side length parameters of the optimized atomic lattice.

Specifically, the purpose of structural optimization is to find a stable structure using the principle of minimum energy. The lower the energy, the more stable the structure. The lattice parameters of the MoSSe atomic lattice can be determined in the crystal database, and the cutoff energy and K point can be measured based on the lattice parameters. The lattice parameters are optimized based on the cutoff energy and K point. The cutoff energy at the lowest energy is 400eV, the K point is 9×9×1, the electron convergence accuracy is 1E-5, and the ion convergence accuracy is 1E-2.

Preferably, the step of sequentially performing self-consistent calculation and non-self-consistent calculation according to the optimized lattice parameters to obtain the pre-processed lattice parameters, and determining the electronic band gap according to the pre-processed lattice parameters comprises:

According to the optimized lattice parameters, self-consistent calculations were performed using Quantum Espresso software to obtain the charge density.

A first K point is selected according to the charge density, and in combination with the charge density, a non-self-consistent calculation is performed using Quantum Espresso software to obtain the pre-processed lattice parameters, wherein the pre-processed lattice parameters include energy bands.

The energy band diagram is plotted according to the energy bands, and the electronic band gap is determined according to the energy band diagram.

Specifically, the energy band diagram is shown in Figure 5. Self-consistent calculation is based on structural optimization. When the system energy reaches a lower level and the system is more stable, the position coordinates of the atoms are fixed, and then the electrons in the system are adjusted to achieve the lowest energy of the system. Non-self-consistent calculation is to change the K point or regenerate parameters such as the K point on the basis of self-consistency, select energy or potential function or electron density as the initial value according to different needs, and perform non-self-consistent iterative calculation, which can be used to analyze the electronic structure of the energy band or other properties such as optics. In this embodiment, the non-self-consistent calculation is to select the first K point, which is a high-symmetry K point, and perform non-self-consistent iterative calculation according to the charge density obtained by self-consistent calculation. The lattice structure has translational symmetry and point group symmetry. There are many repetitive processes when calculating the energy band. The high-symmetry K point is located in the Brillouin zone of the lattice structure. The energy band is calculated in the Brillouin zone in combination with the high-symmetry K point, which can reduce the occupation of computing resources.

Preferably, performing non-self-consistent calculation according to the preprocessed lattice parameters to obtain a wave function comprises:

According to the preprocessed lattice parameters, non-self-consistent calculations are performed using Quantum Espresso software to obtain the wave functions at various positions on the energy band.

A second K point is selected, the energy band is divided using the second K point, and a wave function of the second K point is determined.

Specifically, the second K point is a dense K point with a size of 24×24×1, which contains 576 desymmetric points. When the number of desymmetric points contained in any K point is greater than the preset threshold, the K point is a dense K point, and the corresponding position of the energy band is extracted by using the grid division corresponding to the second K point. The grid corresponding to the K point is also 24×24×1. The energy band range covers 15eV above and below the Fermi level to ensure the convergence of the low-energy band spectrum.

Preferably, performing GW-BSE calculation according to the wave function to obtain the optical band gap comprises:

The electronic band gap corresponding to the first K point is determined, and a convergence calculation is performed on the electronic band gap corresponding to the first K point to obtain a translation value of the band gap.

Specifically, the direct band gap and/or indirect band gap of the high symmetry K point is converged and calculated through vacuum layer Coulomb cutoff approximation, random phase approximation, Hartree (unit of Hartree-Fock energy) approximation, PPA (Proximal Point Algorithm, proximal point) approximation, etc. to obtain the translation value of the band gap.

A GW approximate calculation is performed according to the shift value of the band gap and the wave function of the second K point to obtain a GW approximate value.

Specifically, the GW approximation is used to calculate the self-energy of a multi-body system. The self-energy of the system is expanded using the Green function and the shielded interaction W. The GW approximation is to intercept the first term of the expansion to obtain the GW approximation.

The optical band gap is obtained by performing a BSE calculation in combination with a preset number of conduction bands, a preset number of valence bands, a preset polarization direction and the GW approximation.

Specifically, the Bethe-Salpeter equation is used to calculate and obtain the imaginary part of the dielectric function, and the optical band gap is determined according to the imaginary part of the dielectric function. In addition, the electronic absorption spectrum and the exciton absorption spectrum calculated by GW-BSE are shown in FIG6 .

Preferably, the simulating according to the correction parameters and the control parameters to obtain a plurality of second-order nonlinear non-zero response spectra of the transition metal sulfide comprises:

The correction parameters are introduced by using the yambo_nl module in the Yambo software package (multi-body perturbation theory software package). The incident direction of the incident light is changed by changing the control parameters, and the nonlinear optical properties of the transition metal sulfide are simulated to obtain multiple second-order nonlinear non-zero response spectra of the transition metal sulfide.

Specifically, the second-order nonlinear non-zero response spectrum is finally obtained as shown in Figure 7. According to the principle of the second harmonic effect, only the central asymmetric structure can produce the second harmonic effect. According to the different oscillation directions of the incident light and the outgoing light field, the nonlinear response tensor method can be used to describe the second harmonic generation effect of the system. Since the oscillation direction is divided into three directions of xyz, the complete nonlinear response tensor contains 27 components. For lattices with specific non-central symmetric point groups, only a few of the 27 components are non-zero and unequal depending on the symmetry operation. For the _MoS2 lattice before the atoms are replaced, there are only 4 equal non-zero components, yyy＝-xxy＝-yxx＝-xyx. However, for the MoSSe lattice with an out-of-plane asymmetric structure after the atoms are replaced, it has 10 kinds of 4 groups of different non-zero components (yyy＝-xxy＝-yxx＝-xyx, yyz＝yzy, zyz＝zzy, zyy, zzz). Therefore, there are more available oscillation directions.

As shown in FIG8 , an embodiment of the present invention provides a device for regulating the nonlinear optical properties of transition metal sulfides, including:

The replacement module is used to replace an atom in the transition metal sulfide structure with a calibration atom to obtain a new atomic lattice.

The optimization module is used to optimize the lattice parameters of the new atomic lattice to obtain optimized lattice parameters.

The first processing module is used to perform self-consistent calculation and non-self-consistent calculation in sequence according to the optimized lattice parameters to obtain the pre-processed lattice parameters, and determine the electronic band gap according to the pre-processed lattice parameters.

The second processing module is used to perform non-self-consistent calculation according to the pre-processed lattice parameters to obtain a wave function, and perform GW-BSE calculation according to the wave function to obtain an optical band gap.

A correction module is used to determine a band gap difference according to the optical band gap and the electronic band gap, and to determine a correction parameter according to the band gap difference.

The simulation module is used to perform simulation according to the correction parameters and preset control parameters to obtain multiple second-order nonlinear non-zero response spectra of the transition metal sulfide.

Preferably, the first processing module is specifically used for:

According to the optimized lattice parameters, self-consistent calculations were performed using Quantum Espresso software to obtain the charge density.

A first K point is selected according to the charge density, and in combination with the charge density, a non-self-consistent calculation is performed using Quantum Espresso software to obtain the pre-processed lattice parameters, wherein the pre-processed lattice parameters include energy bands.

The energy band diagram is plotted according to the energy bands, and the electronic band gap is determined according to the energy band diagram.

Preferably, the second processing module is specifically used for:

According to the preprocessed lattice parameters, non-self-consistent calculations are performed using Quantum Espresso software to obtain the wave functions at various positions on the energy band.

A second K point is selected, the energy band is divided using the second K point, and a wave function of the second K point is determined.

Preferably, the second processing module is further used for:

The electronic band gap corresponding to the first K point is determined, and a convergence calculation is performed on the electronic band gap corresponding to the first K point to obtain a translation value of the band gap.

A GW approximate calculation is performed according to the shift value of the band gap and the wave function of the second K point to obtain a GW approximate value.

The optical band gap is obtained by performing a BSE calculation in combination with a preset number of conduction bands, a preset number of valence bands, a preset polarization direction and the GW approximation.

Preferably, the simulation module is specifically used for:

The correction parameters are introduced by using the yambo_nl module in the Yambo software package. The incident direction of the incident light is changed by changing the control parameters, and the nonlinear optical properties of the transition metal sulfide are simulated to obtain multiple second-order nonlinear non-zero response spectra of the transition metal sulfide.

Another embodiment of the present invention provides a device for controlling the nonlinear optical properties of transition metal sulfides, comprising a memory and a processor; the memory is used to store a computer program; the processor is used to implement the method for controlling the nonlinear optical properties of transition metal sulfides as described above when executing the computer program. The device can be a computer, a server, etc.

Still another embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for regulating the nonlinear optical properties of transition metal sulfides as described above is implemented.

A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc. In the present application, the unit described as a separate component may or may not be physically separated, and the component displayed as a unit may or may not be a physical unit, that is, it may be located in one place, or it may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment of the present invention. In addition, each functional unit in each embodiment of the present invention can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims (7)

1. A method for modulating nonlinear optical properties of a transition metal sulfide, comprising:

Replacing one atom in the transition metal sulfide structure with a calibration atom to obtain a new atom lattice;

Optimizing the lattice parameter of the new atomic lattice to obtain an optimized lattice parameter;

sequentially performing self-consistent calculation and non-self-consistent calculation according to the optimized lattice parameter to obtain a preprocessed lattice parameter, and determining an electronic band gap according to the preprocessed lattice parameter;

Non-self-consistent calculation is carried out according to the preprocessed lattice parameter, a wave function is obtained, GW-BSE calculation is carried out according to the wave function, and an optical band gap is obtained;

determining a bandgap difference from the optical bandgap and the electronic bandgap, and determining a correction parameter from the bandgap difference;

simulating according to the correction parameters and preset control parameters to obtain a plurality of second-order nonlinear non-zero response spectrums of the transition metal sulfide;

The step of sequentially performing self-consistent calculation and non-self-consistent calculation according to the optimized lattice parameter to obtain a preprocessed lattice parameter, and the step of determining the electronic band gap according to the preprocessed lattice parameter comprises the following steps: according to the optimized lattice parameter, self-consistent calculation is carried out by adopting Quantum Espresso software, and charge density is obtained; selecting a first K point according to the charge density, and combining the charge density, and adopting Quantum Espresso software to perform non-self-consistent calculation to obtain the pretreated lattice parameter, wherein the pretreated lattice parameter comprises an energy band; drawing the energy band diagram according to the energy band, and determining the electronic band gap according to the energy band diagram;

And performing non-self-consistent calculation according to the preprocessed lattice parameter, wherein the obtaining the wave function comprises the following steps: according to the preprocessed lattice parameters, non-self-consistent calculation is carried out by adopting Quantum Espresso software, and the wave function of each position on the energy band is obtained; and selecting a second K point, dividing the energy band by adopting the second K point, and determining a wave function of the second K point.

2. The method for tuning nonlinear optical properties of a transition metal sulfide according to claim 1, wherein optimizing the lattice parameter of the new atomic lattice to obtain the optimized lattice parameter comprises:

Optimizing the lattice parameter of the new atomic lattice by adopting VASP software, determining a lattice parameter simulation result when the new atomic lattice energy is the lowest point through simulation, determining the optimized lattice parameter according to the lattice parameter simulation result, wherein when the new atomic lattice energy is the lowest point, A and c are the unit cell side length parameters of the optimized atomic lattice.

3. The method for tuning nonlinear optical properties of transition metal sulfides according to claim 2, wherein said performing GW-BSE calculation based on said wave function to obtain an optical bandgap comprises:

determining the electronic band gap corresponding to the first K point, and performing convergence calculation on the electronic band gap corresponding to the first K point to obtain a translation value of the band gap;

performing GW approximate calculation according to the translation value of the band gap and the wave function of the second K point to obtain a GW approximate value;

And carrying out BSE calculation by combining a preset conduction band number, a preset valence band number, a preset polarization direction and the GW approximation value to obtain the optical band gap.

4. The method for adjusting and controlling nonlinear optical properties of a transition metal sulfide according to claim 3, wherein the simulating according to the correction parameter and a preset control parameter to obtain a plurality of second-order nonlinear non-zero response spectrums of the transition metal sulfide comprises:

And introducing the correction parameters by adopting a yambo _nl module in Yambo software package, changing the incidence direction of incident light by changing the control parameters, and simulating the nonlinear optical properties of the transition metal sulfide to obtain a plurality of second-order nonlinear non-zero response spectrums of the transition metal sulfide.

5. A device for controlling nonlinear optical properties of transition metal sulfides, comprising:

The replacement module is used for replacing one atom in the transition metal sulfide structure with a calibration atom to obtain a new atom lattice;

the optimizing module is used for optimizing the lattice parameter of the new atomic lattice to obtain the optimized lattice parameter;

The first processing module is used for sequentially carrying out self-consistent calculation and non-self-consistent calculation according to the optimized lattice parameter to obtain a preprocessed lattice parameter, and determining an electronic band gap according to the preprocessed lattice parameter;

The second processing module is used for carrying out non-self-consistent calculation according to the preprocessed lattice parameter to obtain a wave function, and carrying out GW-BSE calculation according to the wave function to obtain an optical band gap;

a correction module for determining a bandgap difference from the optical bandgap and the electronic bandgap, and determining a correction parameter from the bandgap difference;

The simulation module is used for simulating according to the correction parameters and preset control parameters to obtain a plurality of second-order nonlinear non-zero response spectrums of the transition metal sulfide;

The first processing module is specifically configured to: according to the optimized lattice parameter, self-consistent calculation is carried out by adopting Quantum Espresso software, and charge density is obtained; selecting a first K point according to the charge density, and combining the charge density, and adopting Quantum Espresso software to perform non-self-consistent calculation to obtain the pretreated lattice parameter, wherein the pretreated lattice parameter comprises an energy band; drawing the energy band diagram according to the energy band, and determining the electronic band gap according to the energy band diagram;

The second processing module is specifically configured to: according to the preprocessed lattice parameters, non-self-consistent calculation is carried out by adopting Quantum Espresso software, and the wave function of each position on the energy band is obtained; and selecting a second K point, dividing the energy band by adopting the second K point, and determining a wave function of the second K point.

6. The device for regulating and controlling the nonlinear optical property of the transition metal sulfide is characterized by comprising a memory and a processor;

the memory is used for storing a computer program;

the processor for implementing a method for tuning the nonlinear optical properties of a transition metal sulfide as defined in any one of claims 1 to 4 when executing the computer program.

7. A computer-readable storage medium, characterized in that the storage medium has stored thereon a computer program which, when executed by a processor, implements a method for regulating the nonlinear optical properties of a transition metal sulfide according to any one of claims 1 to 4.