Theoretical Study For The Doping Regulation On Physical Property Of Typical Two-and Three-dimensional Materials

Doping,as an important means to regulate the electronic structure of materials in the fields of solid state chemistry and material chemistry,can effectively modulate the physical and chemical properties of materials such as magnetism,spintronics,superconductivity,and catalysis.This paper selects hexagonal boron nitride,ternary hydrides and transition metal chalcogenides as the research objects,uses the first-principle calculation method to conduct theoretical research on the doping regulation of atoms,electrons and holes,and expounds the relationship between doping structure and magnetism.properties,superconducting properties,and electronic properties,revealing the regulation of doping on the physical and chemical properties of typical two-dimensional and three-dimensional materials.The main research content and results of the paper are as follows:1.Using first-principles calculations,through atomic doping and vacancy defect regulation,explore the influence of doped structure and defect states on the magnetic properties of hexagonal boron nitride materials.Calculate the electronic structure of different concentrations of carbon atom doping and hole defect,reveal the relationship between electronic structure and spin polarization and magnetic moment change,and realize the regulation of electronic spin.Designing a local C-B-B structure with doped defects can realize the controllable modulation of non-spin polarization and local atomic magnetic moment,laying a theoretical foundation for rational design of material structure and synthetic chemistry.2.Explore electron or hole doping modulation to realize dynamically stable ternary hydride electronic state optimization and superconductivity under pressure.By 0.28 e/cell electron doping and 0.86 e/cell hole doping,the La BH₈ van Hove singularity coincides with the Fermi level,and realizes the maximum electron density of states at the Fermi surface in the local area.The pressure drop reduces the lattice stability,and the hole doping of 0.7 e/cell realizes the superconductivity of La BH₈ under the pressure condition of 30 GPa,which provides a theoretical basis for electron or hole doping to optimize the solid electronic state to achieve superconductivity.3.Use electron/hole doping to effectively increase the electronic density of states at the Fermi level of the unit cell Hf S₂ and Ti S₂,and increase the possibility of forming Cooper pairs.From 0.01 e/cell to 0.1 e/cell electron doping concentration increases,the Fermi surface density of states gradually increases and exhibits conductivity,which provides a theoretical basis for the electronic structure regulation of topological quantum materials.