Application Of LDA-1/2 Band Calculation Method In Semiconductors

Both ionic and covalent semiconductors are currently the focus of research in materials science,and they are also widely used in production and life,occupying a pivotal position in the optoelectronics field.Ferreira's LDA-1/2 method corrects the self-energy of holes in real space,and can quickly and accurately calculate the band energy of ionic semiconductors,but the effect is not ideal when applied to covalent semiconductors.Based on this defect,my supervisor proposed an improved algorithm based on the LDA-1/2 method called shellLDA-1/2(referred to as shLDA-1/2),this method introduced a spherical shell-like selfpotential truncation function to solve the common problem.In the special problem of valence semiconductor structure,a variational parameter was added in the self-energy correction process,which greatly improved the calculation result.This article will systematically study ionic and covalent semiconductors based on LDA-1/2 and shLDA-1/2methods.In the research of ionic semiconductors,the self-energy potential library of the main group and important sub-group elements is first established.The establishment of the selfenergy potential library provides great convenience for semiconductor computing.Then the relationship between the element's self-energy potential and the functional taken is analyzed based on the calculated results.Finally,LDA,LDA-1/2,and shLDA-1/2 were used to calculate a large number of ionic semiconductors containing oxygen groups and halogens and the recommended cutoff radii of nonmetal atoms such as oxygen groups and halogens were obtained.In the study of covalent semiconductors,the cutoff radii(outer cut and inner cut)of nonmetal atoms in bulk covalent semiconductors and two-dimensional sulfide covalent semiconductors were calculated using the shLDA-1/2 algorithm.The relationship between the electronegativity of metal atoms,the atomic radius,and the lattice constant.At the same time,by analyzing the positions of the conduction band electrons and valence band holes in the semiconductor to select a reasonable calculation method,the results show that the use of shLDA-1/2 to calculate covalent semiconductors is more reasonable than traditional LDA-1/2.