Method for calculating two-dimensional super-atomic crystal based on cluster
Through the cluster calculation method, the energy gap value of the two-dimensional superatomic crystal TM6E8X2 is calculated, which solves the problem that the experimental process of regulating the band gap of two-dimensional materials in the existing technology is difficult to control, and the accurate screening and calculation of the band gap of two-dimensional superatomic crystal is realized, providing a foundation for the research and development of optoelectronic devices.
Patent Information
- Application Number
- CN202311537675.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-17
- Publication Date
- 2025-05-20
AI Technical Summary
The existing methods of regulating the band gap of two-dimensional materials have problems such as difficult to control the experimental process, and the adjustment effect of the applied electric field is difficult to maintain, which may cause adverse effects such as quantum tunneling effects.
Using a cluster calculation method, the atomic structure model of the TM6E8X2 cluster is constructed, and the energy gap value of the cluster is calculated using first-principle quantum mechanics simulation software, and the band gap of the target two-dimensional superatomic crystal is determined.
Accurate calculation and screening of two-dimensional superatomic crystal band gaps is achieved, reducing the difficulty of research and development, and providing a foundation for the preparation of photocatalytic materials and other optoelectronic devices.
Smart Images
Figure CN120020967A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of semiconductor material bandgap calculation, and particularly relates to a method for calculating two-dimensional superatomic crystals based on clusters. Background Art
[0002] So far, two-dimensional materials have developed materials such as transition metal dichalcogenides, transition metal carbides / nitrides, transition metal oxides, germanene, and phosphorene. Due to their asymmetric characteristics, two-dimensional materials have non-three-dimensional topological structures, ferromagnetism, charge density waves, and other optoelectronic properties, and can be applied to emerging fields such as electronics, photonics, valleytronics, spintronics, as well as nanoscale catalysis and energy conversion.
[0003] The bandgap is an important property of two-dimensional materials, which determines a series of basic physical properties, such as photon excitation, electron transport, etc. Developing methods to regulate the bandgap helps to further construct two-dimensional material-based electronic and optoelectronic devices with adjustable properties and promote the practical application of two-dimensional materials. Currently, methods for regulating the bandgap of two-dimensional materials include stress regulation, applying an electric field, element doping, etc. Stress regulation generally requires precise design, such as stress magnitude, direction, and application method, etc.; the effect of applying stress is closely related to specific application conditions and has high requirements for the preparation process of experimental samples; the method of applying an electric field is convenient for adjustment, but once the electric field disappears, the effect of energy band regulation will be difficult to maintain. At the same time, if the electric field strength is too large, adverse effects such as quantum tunneling effects may occur; the method of atomic doping can be regulated in multiple aspects such as doping concentration, type, and incorporation method, etc. However, in the preparation process, it is difficult to control the concentration and doping position of doped atoms, and it has a great impact on the structural stability of the material. Generally speaking, although the current methods have successfully regulated the bandgap of two-dimensional functional materials, due to problems such as difficult control in experimental processes, new methods for regulating and designing two-dimensional functional materials with different bandgaps need to be developed. Summary of the Invention
[0004] To solve the deficiencies of the prior art, the present invention provides a method for calculating two-dimensional superatomic crystals based on clusters. The present invention uses TM 6 E 8 X 2 clusters as the material construction units, and based on the calculated energy gap values of the clusters, it can be used to determine the target two-dimensional superatomic crystal TM 6 E 8 X 2 (X = F, Cl, Br, I), and then the bandgap of the target two-dimensional superatomic crystal TM 6 E 8 X 2 can be calculated.
[0005] The technical solutions provided by the present invention are as follows:
[0006] A method for calculating two-dimensional superatomic crystals based on clusters, comprising the following steps:
[0007] 1) Calculate the energy gaps of different TM 6 E 8 X 2 clusters, where X = F, Cl, Br or I;
[0008] 2) According to the results of step 1), determine the target TM 6 E 8 X 2 two-dimensional superatomic crystal;
[0009] 3) Calculate the band gap of the target TM 6 E 8 X 2 two-dimensional superatomic crystal.
[0010] The inventor found that based on the TM 6 E 8 X 2 material, by modifying the cluster with a halogen ligand and using the modified cluster as a building block, the calculated energy gap value of the cluster can be used as a reference value for the band gap of the TM 6 E 8 X 2 two-dimensional superatomic crystal. Thus, it can be used to screen out the target TM 6 E 8 X 2 two-dimensional superatomic crystal, and then perform the corresponding band gap calculation.
[0011] In the general formula TM 6 E 8 X 2 TM is selected from transition metal elements such as scandium, titanium, vanadium, chromium, manganese, rhenium, iron or tungsten, and E is selected from chalcogen elements such as sulfur, selenium or tellurium.
[0012] Specifically, step 1) includes the following steps:
[0013] 1a) Use quantum mechanics simulation software based on the first principles of density functional theory to establish the atomic structure model of the TM 6 E 8 X 2 cluster;
[0014] 1b) Based on the conjugate gradient algorithm or quasi-Newton algorithm, use the first principles quantum chemistry calculation software to optimize the geometric structure of the atomic model of the cluster to obtain the model with the lowest total internal energy;
[0015] 1c) Calculate the energy level diagram of the optimized cluster structure model in step 1b) and calculate the energy gap.
[0016] Further, in step 1b), the initially constructed cluster atomic model is optimized by performing structural relaxation, with the k-point set to 2×2×1 and the cut-off energy set to 550 eV.
[0017] Specifically, in step 1), different TMs 6 E 8 X 2 The energy gaps of the clusters decrease in the order of F, Cl, Br, and I. In step 2), different TMs 6 E 8 X 2 The energy gaps of the two-dimensional superatomic crystals decrease in the order of F, Cl, Br, and I.
[0018] Based on the above technical solutions, different TMs 6 E 8 X 2 The energy gaps of the clusters decrease in the order of F, Cl, Br, and I. Correspondingly, different TMs 6 E 8 X 2 The energy gaps of the two-dimensional superatomic crystals also decrease in the order of F, Cl, Br, and I. Therefore, the specific TM 6 E 8 X 2 can be determined according to the changing trend of the energy gap of the cluster, and which specific TM 6 E 8 X 2 two-dimensional superatomic crystal to be used as the target crystal. For example, when a material with the lowest band gap is needed, since the energy gap of the TM 6 E 8 X 2 cluster is the lowest, the target material can be selected as the TM 6 E 8 I 2 two-dimensional superatomic crystal. 6 E 8 I 2 two-dimensional superatomic crystal.
[0019] Specifically, step 3) includes the following steps:
[0020] 3a) Based on the conjugate gradient algorithm or the quasi-Newton algorithm, use first-principles quantum chemistry calculation software to perform sufficient structural relaxation on the target superatomic lattice model;
[0021] 3b) Based on the two-dimensional superatomic lattice model optimized in step 3a), use first-principles quantum chemistry calculation software based on the conjugate gradient algorithm to calculate its three-dimensional energy band using the conjugate gradient algorithm, so as to obtain its band gap.
[0022] Specifically, in step 3a), the parameters for structural relaxation are as follows: the k-point is set to 2×2×1, the cutoff energy is 550 eV, and the convergence criteria for force and energy are and 10 -6 eV.
[0023] Specifically, step 2) includes the following steps: comparing the energy gap values of different TM 6 E 8 X 2 clusters, and screening out the target TM 6 E 8 X 2 two-dimensional superatomic crystals that meet the requirements.
[0024] Advantages of the present invention:
[0025] Based on the first-principles calculation method, the present invention is simple to operate, highly accurate, widely applicable, and has good repeatability;
[0026] Through the calculation of the present invention, two-dimensional superatomic crystal semiconductor materials can be screened, providing a basis for the preparation of photocatalytic materials and other optoelectronic devices, and reducing the R & D difficulty. Description of the drawings
[0027] Figure 1 is the atomic structure model of Re 6 Se 8 X 2 in the embodiment, where the gray color represents Se atoms, the brown color represents X atoms, and the green color represents Re atoms.
[0028] Figure 2 is the electronic configuration of the Re 6 Se 8 X 2 cluster in the embodiment. From left to right, X = F, Cl, Br, and I, and the gray solid and dashed lines represent occupied and unoccupied electronic states, respectively.
[0029] Figure 3 is the atomic structure model of the superatomic crystal Re 6 Se 8 X 2 (X = F, Cl, Br, or I) in the embodiment, where the gray color represents Se atoms, the brown color represents X atoms, and the green color represents Re atoms.
[0030] Figure 4 is the three-dimensional energy band diagram of the superatomic crystal Re 6 Se 8 X 2 (X = F, Cl, Br, or I) obtained in the embodiment. Detailed implementation manners
[0031] The principles and features of the present invention will be described below. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.
[0032] Example 1
[0033] 1. Taking Re 6 Se 8 X 2 (X = F, Cl, Br or I) as an example, a cluster atomic structure model as shown in Figure 1 is constructed.
[0034] 2. Based on the conjugate gradient algorithm, the first-principles quantum chemistry calculation software is used to perform sufficient structural relaxation on each initially constructed cluster atomic model. In this step, the k-point is set to 2×2×1, the cut-off energy is 550 eV, and the spin multiplicities S are set to 1, 3, 5, 7, and 9 respectively. The calculation results are shown in the following table. According to the principle of the lowest energy, it is determined that the ground state of the cluster Re 6 Se 8 X 2 is spin singlet, the ground state of Re 6 Se 8 F 2 is spin singlet, the ground state of Re 6 Se 8 Cl 2 is spin singlet, the ground state of Re 6 Se 8 Br 2 is spin singlet, and the ground state of Re 6 Se 8 I 2 is spin singlet.
[0035] Table 1 Energies (eV) of the Re 6 Se 8 X 2 (X = F, Cl, Br, I) cluster in different spin states. Based on the ground state.
[0036]
[0037]
[0038] 3. Based on the ground state calculation results of step 2, the energy level positions of the Re 6 Se 8 X 2 (X = F, Cl, Br, I) cluster are calculated using the first-principles quantum chemistry calculation software based on the conjugate gradient algorithm, and the highest occupied molecular orbital energy level (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy level positions are calibrated. The band gap Eg is calculated according to formula 1, and the results are as shown in Figure 2 .
[0039] E gap = E LUMO -E LUMO
[0040] Table 2. Re 6 Se 8 X 2 (X = F, Cl, Br, I) Summary of the structural information and electronic properties of clusters.
[0041]
[0042] 4. Based on Step 2, based on the Bader electron population idea, use the vaspkit software package to analyze the number of electrons gained and lost by halogen atoms in the cluster Re 6 Se 8 X 2 (X = F, Cl, Br, I).
[0043]
[0044] q A is the charge of atom A;
[0045] Z A is the number of valence electrons of atom A;
[0046] Ω A represents the independent space of atom A divided by the zero-flux surface of electron density;
[0047] ρ is a function of electron density.
[0048] 5. Based on Step 3, in the way of bonding between Re atoms and Se atoms, using the cluster as the basic design unit, construct the Re Figure 3 as shown 6 Se 8 X 2 superatomic periodic crystal.
[0049] 6. Based on the conjugate gradient algorithm, use the first-principles quantum chemistry calculation software to perform full structural relaxation on each initially built superatomic lattice model. In this step, the k-point is set to 2×2×1, the cut-off energy is 550 eV, and the convergence criteria for force and energy are respectively and 10 -6 eV.
[0050] 7. Based on the two-dimensional superatomic lattice model optimized in Step 6, use the first-principles quantum chemistry calculation software based on the conjugate gradient algorithm to calculate its three-dimensional energy band, so as to obtain its band gap, and the results are as Figure 4 shown.
[0051] 8. Based on Step 7 and the Bader electron number layout idea, the vaspkit software package is used to analyze the electron transfer number of halogen atoms in the two-dimensional superatomic crystal Re 6 Se 8 X 2 (X = F, Cl, Br, or I). Table 3 summarizes the structural parameters and electronic structure properties of two-dimensional periodic crystals. This table includes the optimized structural parameters (a and b, ), the bond lengths (Bond Re-X , ) between Re and halogen atoms, the bandgap (bandgap, eV) of two-dimensional periodic crystals, the charge (C, e) of a single
[0052] halogen atom, and the work function (WF, eV) of two-dimensional periodic crystals.
[0053] System a b <![CDATA[Bond Re-X > bandgap C WF <![CDATA[Re 6 Se 8 F 2 > 6.69 6.73 1.95 1.69 0.9 6.87 <![CDATA[Re 6 Se 8 Cl 2 > 6.68 6.71 2.35 1.63 0.45 6.89 <![CDATA[Re 6 Se 8 Br 2 > 6.68 6.72 2.51 1.55 0.4 6.81 <![CDATA[Re 6 Se 8 I 2 > 6.68 6.72 2.73 1.40 0.2 6.60
[0054] After proceeding to Step 3, the bandgap values of each cluster of Re 6 Se 8 X 2 (X = F, Cl, Br, I) can be obtained. The bandgaps of each two-dimensional superatomic crystal of Re 6 Se 8 X 2 (X = F, Cl, Br, I) have the same changing trend. Therefore, the two-dimensional superatomic crystal of Re 6 Se 8 X 2 (X = F, Cl, Br, I) with the largest or smallest bandgap can be determined directly according to the bandgap values of each cluster, and then the target two-dimensional superatomic crystal of Re 6 Se 8 X 2 can be determined as needed. Since the target two-dimensional superatomic crystal of Re 6 Se 8 X 2 is determined, the bandgap of the target two-dimensional superatomic crystal of Re 6 Se 8 X 2 can be calculated. 6 Se 8 X 2 In addition, through the calculations in Step 4 and Step 8, it can be found that the changing rule of the bandgap values of the Re
[0055] Se 6 Se 8 X 2 cluster and the Re 6 Se 8 X 2The variation law of the band gap of the two-dimensional superatomic crystal conforms to the variation law of the number of electrons gained or lost by X, thus verifying Re 6 Se 8 X 2 The variation law of the band gap value of the cluster and Re 6 Se 8 X 2 The consistency of the variation law of the band gap of the two-dimensional superatomic crystal.
[0056] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for cluster-based calculation of two-dimensional superatomic crystals, characterized in that: The following steps are involved: 1) Calculate the energy gap of different TM6E8X2 clusters, X = F, Cl, Br or I; 2) According to the result of step 1), determine the target TM6E8X2 two-dimensional superatomic crystal; 3) Calculate the band gap of the target TM6E8X2 two-dimensional superatomic crystal.
2. The method for cluster computing of two-dimensional superatomic crystals according to claim 1, characterized in that: Step 1) comprises the following steps: 1a) Using first-principles quantum mechanics simulation software based on density functional theory to establish the atomic structure model of TM6E8X2 cluster; 1b) Based on the conjugate gradient algorithm or the quasi-Newton algorithm, the first-principles quantum chemical calculation software is used to optimize the geometric structure of the atomic model of the cluster to obtain the model with the lowest total internal energy; 1c) Calculate the energy level diagram of the cluster structure model after optimization in step 1b) and calculate the energy gap.
3. The method for cluster computing of two-dimensional superatomic crystals according to claim 2, characterized in that: In step 1b), the optimization is performed by structural relaxation of the initially constructed cluster atomic model, with the K point set to 2×2×1 and the cutoff energy to 550 eV.
4. The method for cluster computing of two-dimensional superatomic crystals according to claim 2, characterized in that: Step 3) comprises the following steps: 3a) Based on the conjugate gradient algorithm or the quasi-Newton algorithm, the first-principles quantum chemical calculation software is used to fully relax the structure of the target superatomic lattice model; 3b) Based on the two-dimensional superatomic lattice model optimized in step 3a), the three-dimensional energy band is calculated using the conjugate gradient algorithm using first-principles quantum chemical calculation software to obtain its band gap.
5. The method for cluster computing of two-dimensional superatomic crystals according to claim 4, characterized in that: In step 3a), the parameters for structural relaxation are: K point is set to 2×2×1, cutoff energy is 550 eV, and the convergence criteria for force and energy are and 10 -6 eV.
6. The method for cluster computing of two-dimensional superatomic crystals according to any one of claims 1 to 5, characterized in that: Step 2) includes the following steps: comparing the energy gap values of different TM6E8X2 clusters, and screening out target TM6E8X2 two-dimensional superatomic crystals that meet the requirements.
7. The method for cluster computing of two-dimensional superatomic crystals according to claim 6, characterized in that: In step 1), the energy gaps of different TM6E8X2 clusters decrease in the order of F, Cl, Br, and I; In step 2), the energy gaps of different TM6E8X2 two-dimensional superatomic crystals decrease in the order of F, Cl, Br, and I.
8. The method for cluster computing of two-dimensional superatomic crystals according to claim 1, characterized in that: In the general formula TM6E8X2, TM is selected from scandium, titanium, vanadium, chromium, manganese, rhenium, iron or tungsten, and E is selected from sulfur, selenium or tellurium.