Estudo das propriedades estruturais e eletrônicas de semicondutores (GaAs, SiC e Si) via Teoria do Funcional da Densidade (DFT)

Abstract

Density Functional Theory (DFT) is a powerful and widely used computational tool for investigating the properties of materials at the atomic level. Its ability to provide detailed information about the electronic structure and other physical properties of materials makes it an indispensable tool in materials science and solid-state physics. The aim of this work was to determine the structural and electronic properties of some semiconductors. The combination of technical skills in Linux/UNIX and Fortran 90, along with specific training in the Wien2k software, enabled accurate and comprehensive simulations in the advanced study of materials physics. The training included the simulation and optimization of the crystalline structure of semiconductor materials (Si, SiC, and GaAs), self-consistent calculation of their electronic structures, as well as analysis and interpretation of the obtained results. Different exchangecorrelation functionals were compared, including the Local Density Approximation (LDA), the Generalized Gradient Approximation (GGA) parametrized by Perdew-Burke-Ernzerhof (PBEGGA), and its solid-state modification (GGA-PBESOL). The results obtained showed good agreement with values found in the literature regarding lattice parameters and electronic properties. However, for a more accurate prediction of the bandgap, it was necessary to introduce the modified Becke-Johnson (mBJ) potential correction in some compounds, resulting in values closer to the experimental ones.