Method for calculating electronic structure and optical property of low-dimensional carbon structure allotrope
By decomposing and correcting the dielectric shielding effect, calculating the dielectric constant matrix and predicting the bandgap width and electronic structural characteristics of the nanoribbon, the problem of insufficient prediction accuracy of electronic structures of low-dimensional materials in the prior art is solved, and high-precision optical Properties prediction.
Patent Information
- Application Number
- CN202411293961.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2025-02-07
AI Technical Summary
The prior art faces problems such as insufficient prediction of higher-order DFT bandgaps, high cost of hybrid functional calculations and limited correlation improvements, and the GW-BSE method that requires substrate effect to be considered.
By constructing the ground state electronic structure of the allotrope of low-dimensional carbon structure, decomposing and correcting the dielectric shielding effect, the modified dielectric shielding effect expression is obtained, and when the hybrid effect of the valence band and conduction band states is considered, Calculate the dielectric constant matrix, solve the band gap width and electronic structural characteristics of the nanoribbon, and finally predict the optical properties of low-dimensional carbon allotropes.
It significantly improves the prediction accuracy of the electronic structure and optical properties of allotropes in low-dimensional carbon structures, effectively captures the complex interaction between nanoribbons and metal substrates, and ensures accurate simulation and prediction of material properties in complex environments.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of condensed matter physics and nanometer materials, in particular to a method for calculating the electronic structure and optical properties of a low-dimensional carbon structure allotrope. Background Art
[0002] With the rapid development of low-dimensional materials (such as graphene, nanoribbons, etc.), new opportunities have been brought to the study of exciton effects. In these materials, due to the weakening of dielectric screening effect, the Coulomb mutual attraction between electrons and holes is enhanced, and excitons become the key factor in determining the transport and optical properties of low-dimensional materials.
[0003] Although the existing theoretical and computational methods have made significant progress in exploring the electronic structure and properties of low-dimensional materials, there are still a series of technical challenges. These challenges not only limit the in-depth understanding of the properties of materials, but also affect the further development of related applications. The following is a detailed description of the main shortcomings of the current background technology:
[0004] First, as an important tool for calculating the electronic structure of materials, high-order density functional theory (DFT) has improved the accuracy of traditional DFT to a certain extent, but it is still limited in dealing with complex systems because it is still not completely out of the DFT framework. In particular, when higher-order partial derivatives are introduced to try to solve the problem of large band gap predictions, the effect is not as significant as expected, indicating that high-order DFT has not fundamentally overcome this problem.
[0005] Second, the hybrid density functional method significantly improves the accuracy of band gap prediction by combining the advantages of the wave function method. However, this progress comes at a huge computational cost. The computational complexity of the hybrid functional far exceeds that of traditional DFT, making it incapable of dealing with large-scale systems or performing large-scale calculations. In addition, although the hybrid functional performs well in improving electron exchange energy, the improvement in electron correlation energy is relatively limited, which limits its accuracy in dealing with widely existing interactions such as van der Waals forces.
[0006] Third, GW-BSE (GW method combined with Bethe-Salpeter equation, G is Green's function, W is dynamic screening Coulomb interaction) as an advanced theoretical method, has shown great potential in predicting the quasiparticle electronic structure, exciton effect and optical properties of low-dimensional materials. The GW method can more accurately describe the quasi-particle state of the material by considering the dynamic screening effect of electrons, while BSE further reveals the formation and properties of excitons. However, it is worth noting that the GW-BSE method still needs to fully consider the substrate effect in practical applications. Because the interaction between the substrate and the material often has an important influence on the electronic structure of the material, ignoring this factor will make it difficult to obtain results that are completely consistent with the experiment. Summary of the invention
[0007] To this end, the technical problem to be solved by the present invention is to overcome the key technical problems faced in the prior art when processing the electronic structure of low-dimensional materials, such as insufficient prediction of high-order DFT band gaps, high calculation cost of hybrid functionals and limited improvement in correlation, and the need to consider substrate effects in the GW-BSE method, and provide a method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes, the method comprising the following steps:
[0008] S1: constructing a ground state electronic structure of a low-dimensional carbon structure allotrope, and obtaining an original expression of the dielectric screening effect based on the ground state electronic structure; wherein the ground state electronic structure includes a nanoribbon and a substrate;
[0009] S2: decomposing the original expression of the dielectric shielding effect into the sum of the nanobelt contribution value and the substrate contribution value, and simplifying and approximating it to obtain a revised dielectric shielding effect expression;
[0010] S3: Under the condition that the hybridization effect of the valence band and the conduction band states is taken into consideration, the dielectric constant matrix is obtained by using the modified dielectric screening effect expression;
[0011] S4: according to the dielectric constant matrix, solving and obtaining the band gap width and electronic structure characteristics of the nanoribbon;
[0012] S5: Based on the electronic structure characteristics, predict the optical properties of low-dimensional carbon allotropes.
[0013] In one embodiment of the present invention, the low-dimensional carbon structure allotrope is composed of a metal substrate and a nanobelt, wherein the nanobelt is arranged on the metal substrate. The lattice constant of the metal substrate is
[0014] In one embodiment of the present invention, in S1, the method for obtaining the original expression of the dielectric shielding effect is: within the multi-body perturbation calculation framework, the original expression of the dielectric shielding effect at the interface between the metal substrate and the nanobelt is approximately calculated as follows:
[0015]
[0016] in, represents the polarizability, and represents the position vector of different electrons in time and space, ω is the angular frequency, n represents the occupied Kohn-Sham orbital, n′ represents the unoccupied Kohn-Sham orbital, E n and E n' are the energy eigenvalues of occupied and unoccupied states, respectively; are the wave functions of different electrons in occupied states; are the wave functions of different electrons in the unoccupied state.
[0017] In one embodiment of the present invention, in S2, the method for obtaining the modified dielectric shielding effect expression is:
[0018] S21: Since the state of the interface is completely confined to the nanobelt or the substrate, let ω=0, decompose the original expression of the dielectric shielding effect into the sum of the nanobelt contribution value and the substrate contribution value, and obtain the first modified dielectric shielding expression;
[0019] S22: The polarizability matrix defined in reciprocal space is and is the inverted lattice vector, wave vector Taking the sampling grid points in the first Brillouin zone, the polarizability matrix in real space is and the polarizability matrix in reciprocal space The conversion relationship between them;
[0020] S23: According to the first modified dielectric shielding expression and the conversion relationship, a modified dielectric shielding effect expression in the reciprocal space is obtained.
[0021] In one embodiment of the present invention, in S21, the first modified dielectric shielding expression is:
[0022]
[0023] In one embodiment of the present invention, in S22, the conversion relationship is:
[0024]
[0025] Here, Ω represents the crystal volume.
[0026] In one embodiment of the present invention, in S23, the modified dielectric shielding effect expression in the reciprocal space is:
[0027]
[0028] in, is the total polarizability in reciprocal space, represents the polarizability of the nanoribbon in reciprocal space, represents the polarizability of the metal substrate in reciprocal space.
[0029] In one embodiment of the present invention, in S3, the dielectric constant matrix is obtained. The calculation method is:
[0030]
[0031] Here, v represents the Coulomb potential.
[0032] The present invention also provides a system for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes, which is used to implement the steps of the method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes, and the system comprises:
[0033] A ground state electronic structure building module is used to build a ground state electronic structure of a low-dimensional carbon structure allotrope, and based on the ground state electronic structure, obtain an original expression of the dielectric shielding effect; wherein the ground state electronic structure includes a nanobelt and a substrate;
[0034] A dielectric shielding effect decomposition and approximation module is used to decompose the original expression of the dielectric shielding effect into the sum of the nanobelt contribution value and the substrate contribution value, and perform simplification and approximation processing to obtain a modified dielectric shielding effect expression;
[0035] A dielectric constant matrix calculation module, used to obtain a dielectric constant matrix by using the modified dielectric shielding effect expression while considering the hybridization effect of the valence band and the conduction band states;
[0036] A band gap width and electronic structure solving module, used for solving the band gap width and electronic structure characteristics of the nanoribbon according to the dielectric constant matrix;
[0037] The optical property prediction module is used to predict the optical properties of low-dimensional carbon allotropes based on the electronic structure characteristics.
[0038] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements instructions for the method of calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes.
[0039] The above technical solution of the present invention has the following advantages compared with the prior art:
[0040] 1. Based on the classic GW-BSE (GW method combined with Bethe-Salpeter equation), this invention cleverly incorporates the consideration of metal substrate effect, realizing a leap-forward expansion from the study of electronic structure and optical properties of single two-dimensional materials to the field of complex one-dimensional materials supported by metal substrates. This innovation not only enriches the theoretical research toolbox of material physics, but also opens up a new path for a deeper understanding of the modulation mechanism of electronic structure and optical properties of metal-low-dimensional material interface interactions.
[0041] 2. By finely decomposing and correcting the dielectric screening effect, the present invention significantly improves the prediction accuracy of the electronic structure and optical properties of low-dimensional carbon structure allotropes. This method can effectively capture the complex interactions between nanoribbons and metal substrates, ensure accurate simulation and prediction of material properties in complex environments, and provide solid data support and theoretical basis for research in the fields of materials science, nanotechnology, and optoelectronic device design.
[0042] 3. The technical solution of the present invention provides an efficient and convenient method system for calculating the optical properties of one-dimensional materials on metal substrates. It not only simplifies the calculation process and reduces the calculation cost, but also greatly shortens the research cycle, allowing researchers to more quickly screen low-dimensional materials with excellent optical properties, accelerate the transformation of related research results into practical applications, and promote scientific and technological progress and development in the fields of optoelectronics, sensors, energy conversion, etc. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein
[0044] Figure 1 It is a schematic diagram of the band gap of bisphenylene and graphene nanoribbons changing with the width of the nanoribbons;
[0045] Figure 2 is a flow chart of a method for calculating the electronic structure and optical properties of a low-dimensional carbon structure allotrope provided in the first embodiment of the present invention;
[0046] Figure 3(a) is a schematic diagram of the electron-electron and electron-hole interactions induced by the metal substrate Au(111) in the bisphenyl nanobelt, and (b) is a top view of the crystal structure of the bisphenyl nanobelt and the metal substrate Au(111);
[0047] Figure 4 The established one-dimensional biphenyl nanoribbon (BPR) nanoribbon structures are cut out along the z-axis direction and are named 6-BPR, 9-BPR and 12-BPR according to the number of CC bonds perpendicular to the z-axis direction.
[0048] Figure 5 The optical absorption spectra and corresponding exciton spectra of 6-BPR, 9-BPR and 12-BPR, where (a) to (c) represent the calculation results of 6-BPR, 9-BPR and 12-BPR in vacuum, respectively; (d) to (f) represent the calculation results of 6-BPR, 9-BPR and 12-BPR considering metal substrate, respectively;
[0049] Figure 6 It is a schematic diagram of the structure of a system for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes provided in the second embodiment of the present invention;
[0050] Explanation of the reference numerals in the specification: 100, ground state electronic structure building module; 200, dielectric screening effect decomposition and approximation module; 300, dielectric constant matrix calculation module; 400, band gap width solution module; 500, electronic structure and optical property prediction module. DETAILED DESCRIPTION
[0051] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.
[0052] Embodiment 1
[0053] The experimentally successfully prepared biphenyl nanoribbons (BPRs) have been reported, and the band gap ( Figure 1 The figure in the figure shows the curve of "BPR-Cai") and the experimental results ( Figure 1The calculated band gap of a BPR with a width of 6 and 6 CC bonds is 1.71eV, which is much smaller than the experimental result of 2.35eV. After careful analysis, the researchers found that the main reason for this difference is that the theoretical calculation did not fully consider the influence of the gold substrate on the electronic structure of BPRs in the experiment. As part of the experimental sample, the presence of the gold substrate will significantly change the dielectric environment around the BPRs, thereby affecting the interaction between electrons and holes and the formation and behavior of excitons. However, in the current DFT calculation model, this substrate effect is often ignored, resulting in deviations between the calculated results and the actual situation.
[0054] Based on the GW-BSE method, the present invention considers the influence of the metal substrate and extends the calculation of the electronic structure and optical properties of two-dimensional materials to the calculation of one-dimensional materials induced by the metal substrate. Figure 2 As shown, a method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes is provided, the steps comprising:
[0055] S1: Based on density functional theory, QUANTUM ESPRESSO is used to construct the ground state electronic structure of low-dimensional carbon structure allotropes. Based on the ground state electronic structure, the generalized plasmon model is used to process the dielectric screening effect in the electron self-energy, and the original expression of the dielectric screening effect is obtained; wherein, the ground state electronic structure includes nanoribbons and substrates;
[0056] S2: The original expression of the dielectric shielding effect is decomposed into the sum of the nanoribbon contribution value and the substrate contribution value through a non-self-consistent state (nscf), and simplified and approximated to obtain a corrected dielectric shielding effect expression;
[0057] S3: Considering the hybridization effect of the valence band and conduction band states, the BERKELEYGW software is used to perform G0W0 calculation and BSE calculation, and the dielectric constant matrix is obtained using the modified dielectric screening effect expression;
[0058] S4: according to the dielectric constant matrix, solving and obtaining the band gap width and electronic structure characteristics of the nanoribbon;
[0059] S5: Based on the electronic structure characteristics, predict the optical properties of low-dimensional carbon allotropes.
[0060] Furthermore, the low-dimensional carbon structure allotrope is composed of a metal substrate and a nanobelt, wherein the nanobelt is arranged on the metal substrate Au(111). The lattice constant of the metal substrate Au(111) is like Figure 3(a) Shows the effect of metal monolayer substrate Au(111) on dielectric shielding in nanoribbons.
[0061] In this embodiment, in S1, the method for obtaining the original expression of the dielectric shielding effect is: within the multi-body perturbation calculation framework, the original expression of the dielectric shielding effect at the interface between the metal substrate and the nanobelt is approximately calculated as follows:
[0062]
[0063] in, represents the polarizability, and represents the position vector of different electrons in time and space, ω is the angular frequency, n represents the occupied Kohn-Sham orbital, n′ represents the unoccupied Kohn-Sham orbital, E n and E n' are the energy eigenvalues of occupied and unoccupied states, respectively; are the wave functions of different electrons in occupied states; are the wave functions of different electrons in the unoccupied state.
[0064] In S2 of this embodiment, the original expression of the dielectric shielding effect is decomposed into the sum of the nanobelt contribution value and the substrate contribution value, and simplified and approximated to obtain a revised dielectric shielding effect expression, and the method steps include:
[0065] S21: Since the state of the interface is completely confined to the nanobelt or the substrate, let ω = 0, and decompose the original expression of the dielectric shielding effect into the sum of the nanobelt contribution value and the substrate contribution value, and obtain the first modified dielectric shielding expression:
[0066]
[0067] S22: The polarizability matrix defined in reciprocal space is and is the inverted lattice vector, wave vector Taking the sampling grid points in the first Brillouin zone, the polarizability matrix in real space is and the polarizability matrix in reciprocal space The conversion relationship between:
[0068]
[0069] Here, Ω represents the crystal volume.
[0070] S23: Figure 3As shown in (b), the modified dielectric shielding effect in the reciprocal space can be approximately regarded as the sum of the polarizability of the nanobelt and the polarizability of the metal substrate. According to the first modified dielectric shielding expression and the conversion relationship, the modified dielectric shielding effect expression in the reciprocal space is obtained:
[0071]
[0072] in, is the total polarizability in reciprocal space, represents the polarizability of the nanoribbon in reciprocal space, represents the polarizability of the metal substrate in reciprocal space.
[0073] In S3, based on the relatively accurate total polarizability obtained by the above calculation, The dielectric constant matrix is calculated by formula (5):
[0074]
[0075] Here, v represents the Coulomb potential.
[0076] In order to verify the effectiveness of the present invention, the electronic structure and optical properties of biphenyl nanoribbons (BPR) were studied based on the above method. As an allotrope of carbon, biphenyl has a rectangular lattice and belongs to the Pmmm space group. Figure 4 The nanoribbon structure shown has been successfully prepared experimentally, and for the stability of the nanoribbon structure, the dangling bond hexagonal edges at break are passivated by hydrogen atoms.
[0077] The band gap width of the nanoribbon structure was calculated using G0W0 without considering the influence of the Au substrate (111) and considering the influence of the Au substrate (111), and the results are shown in Table 1. When the one-dimensional material is suspended in a vacuum, the quasiparticle band gaps of 6-BPR, 9-BPR and 12-BPR are 3.55eV, 2.52eV and 1.82eV, respectively. Compared with the band gaps of 1.08eV, 0.45eV and 0.05eV calculated by PBE, the PBE and G0W0 calculations show that the quasiparticle correction is very obvious. When the metal substrate is considered, the calculated quasiparticle band gaps of 6-BPR, 9-BPR and 12-BPR are 2.23eV, 1.40eV and 0.83eV, respectively, which are very consistent with the experimental reports of 2.35eV, 1.44eV and 0.84eV.
[0078] Table 1
[0079]
[0080]
[0081] In addition to the electronic structure, the optical absorption spectrum and the corresponding exciton effect are calculated based on the quasiparticle energy obtained by GW. The results are shown in Figure 5 As shown, the curve with the legend "w / o substrate" does not consider the electron-hole interaction result, and the curve with the legend "with substrate" considers the electron-hole interaction result. When the electron-hole interaction is considered, the exciton state appears under the quasi-particle band gap. For the bisphenyl nanoribbon in vacuum, the first light absorption peak of 6-BPR appears at 2.81eV, with an exciton binding energy of 1.74eV. The absorption edges of 9-BPR and 12-BPR are located at 1.32eV and 2.56eV, respectively, corresponding to exciton binding energies of 1.42eV and 1.28eV.
[0082] When the influence of the metal substrate is taken into account, the absorption edge of 6-BPR is red-shifted by 0.48eV compared with that in vacuum, and the absorption edges of 9-BPR and 12-BPR are red-shifted by 0.43eV and 0.22eV respectively. The binding energy of the first bright exciton in each BPR system decreases by about 1.0eV. For the 6-BPR, the binding energy of the first bright exciton decreases significantly, and it evolves from a bound state to a resonant state.
[0083] Embodiment 2
[0084] The present invention also provides a system for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes, which is used to implement the steps of the method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes described in embodiment 1, such as Figure 6 As shown, the system comprises:
[0085] A ground state electronic structure building module 100 is used to build a ground state electronic structure of a low-dimensional carbon structure allotrope, and obtain an original expression of a dielectric shielding effect based on the ground state electronic structure; wherein the ground state electronic structure includes a nanobelt and a substrate;
[0086] The dielectric shielding effect decomposition and approximation module 200 is used to decompose the original expression of the dielectric shielding effect into the sum of the nanobelt contribution value and the substrate contribution value, and perform simplification and approximation processing to obtain a modified dielectric shielding effect expression;
[0087] A dielectric constant matrix calculation module 300 is used to obtain a dielectric constant matrix by using the modified dielectric shielding effect expression while considering the hybridization effect of the valence band and the conduction band states;
[0088] A band gap width and electronic structure solving module 400, used to solve and obtain the band gap width and electronic structure characteristics of the nanoribbon according to the dielectric constant matrix;
[0089] The optical property prediction module 500 is used to predict the optical properties of low-dimensional carbon allotropes based on the electronic structure characteristics.
[0090] The present embodiment proposes a system for calculating the electronic structure and optical properties of a low-dimensional carbon structure allotrope, which is used to implement the aforementioned method for calculating the electronic structure and optical properties of a low-dimensional carbon structure allotrope. Therefore, the specific implementation of the system for calculating the electronic structure and optical properties of a low-dimensional carbon structure allotrope can be seen in the aforementioned embodiment of the method for calculating the electronic structure and optical properties of a low-dimensional carbon structure allotrope. For example, the ground state electronic structure building module 100, the dielectric screening effect decomposition and approximation module 200, the dielectric constant matrix calculation module 300, the band gap width and electronic structure solution module 400 and the optical property prediction module 500 are respectively used to implement the steps S1, S2, S3, S4 and S5 in the method for calculating the electronic structure and optical properties of a low-dimensional carbon structure allotrope in the first embodiment. Therefore, its specific implementation can refer to the description of the corresponding embodiments of each part. In order to avoid redundancy, it will not be repeated here.
[0091] Embodiment 3
[0092] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements instructions for the method of calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes described in Example 1.
[0093] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.
[0094] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.
[0095] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.
[0096] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.
[0097] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.
Claims
1. A method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes, characterized in that: The following steps are involved: S1: constructing a ground state electronic structure of a low-dimensional carbon structure allotrope, and obtaining an original expression of the dielectric screening effect based on the ground state electronic structure; wherein the ground state electronic structure includes a nanoribbon and a substrate; S2: decomposing the original expression of the dielectric shielding effect into the sum of the nanobelt contribution value and the substrate contribution value, and simplifying and approximating it to obtain a revised dielectric shielding effect expression; S3: Under the condition that the hybridization effect of the valence band and the conduction band states is taken into consideration, the dielectric constant matrix is obtained by using the modified dielectric screening effect expression; S4: according to the dielectric constant matrix, solving and obtaining the band gap width and electronic structure characteristics of the nanoribbon; S5: Based on the electronic structure characteristics, predict the optical properties of low-dimensional carbon allotropes.
2. The method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes according to claim 1, characterized in that: The low-dimensional carbon structure allotrope is composed of a metal substrate and a nanobelt, wherein the nanobelt is arranged above the metal substrate. The lattice constant of the metal substrate is 3. The method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes according to claim 1, characterized in that: In S1, the original expression of the dielectric shielding effect is obtained by approximating the original expression of the dielectric shielding effect at the interface between the metal substrate and the nanobelt within the multi-body perturbation calculation framework as follows: in, represents the polarizability, and represents the position vector of different electrons in time and space, ω is the angular frequency, n represents the occupied Kohn-Sham orbital, n′ represents the unoccupied Kohn-Sham orbital, E n and E n' are the energy eigenvalues of occupied and unoccupied states, respectively; are the wave functions of different electrons in occupied states; are the wave functions of different electrons in the unoccupied state.
4. The method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes according to claim 3, characterized in that: In S2, the method to obtain the modified dielectric shielding effect expression is: S21: Since the state of the interface is completely confined to the nanobelt or the substrate, let ω=0, decompose the original expression of the dielectric shielding effect into the sum of the nanobelt contribution value and the substrate contribution value, and obtain the first modified dielectric shielding expression; S22: The polarizability matrix defined in reciprocal space is and is the inverted lattice vector, wave vector Taking the sampling grid points in the first Brillouin zone, the polarizability matrix in real space is and the polarizability matrix in reciprocal space The conversion relationship between them; S23: According to the first modified dielectric shielding expression and the conversion relationship, a modified dielectric shielding effect expression in the reciprocal space is obtained.
5. The method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes according to claim 4, characterized in that: In S21, the first modified dielectric shielding expression is:
6. The method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes according to claim 5, characterized in that: In S22, the conversion relationship is: Here, Ω represents the crystal volume.
7. The method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes according to claim 6, characterized in that: In S23, the modified dielectric shielding effect expression in the reciprocal space is: in, is the total polarizability in reciprocal space, represents the polarizability of the nanoribbon in reciprocal space, represents the polarizability of the metal substrate in reciprocal space.
8. The method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes according to claim 7, characterized in that: In S3, the dielectric constant matrix is obtained The calculation method is: Here, v represents the Coulomb potential.
9. A system for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes, characterized in that: Steps for implementing the method for calculating the electronic structure and optical properties of low-dimensional carbon structure allotropes as claimed in any one of claims 1 to 8, the system comprising: A ground state electronic structure building module is used to build a ground state electronic structure of a low-dimensional carbon structure allotrope, and based on the ground state electronic structure, obtain an original expression of the dielectric shielding effect; wherein the ground state electronic structure includes a nanobelt and a substrate; A dielectric shielding effect decomposition and approximation module is used to decompose the original expression of the dielectric shielding effect into the sum of the nanobelt contribution value and the substrate contribution value, and perform simplification and approximation processing to obtain a modified dielectric shielding effect expression; A dielectric constant matrix calculation module is used to obtain a dielectric constant matrix by using the modified dielectric shielding effect expression while considering the hybridization effect of the valence band and the conduction band states; A band gap width and electronic structure solving module, used for solving the band gap width and electronic structure characteristics of the nanoribbon according to the dielectric constant matrix; The optical property prediction module is used to predict the optical properties of low-dimensional carbon allotropes based on the electronic structure characteristics.
10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the computer program implements the instructions of the method for calculating the electronic structure and optical properties of a low-dimensional carbon structure allotrope as claimed in any one of claims 1 to 8.