“First Principle Calculations of Gallium Arsenide Using Density Functional Theory

Abstract

Density functional theory (DFT) has had a rapidly growing impact not only on fundamental but also industrial research. The local density approximation (LDA) and the generalized gradient approximation (GGA) were used to compute the exchange correlation energy. The total minimum energy of GaAs is performed as a function of cutoff energy and Monk horst-pack grid size. The results show that, the total minimum energy of GaAs decreases with increasing cutoff energy due to variational principle. However, there is no systematic trend that can be predicted from just increasing the k point sampling. The total minimum force on GaAs is computed by displacing As atom in the z direction as a function of cutoff energy and k point grid size by 0.05 Bohr. Moreover, the total minimum force is converged at the cutoff 60 Rydberg and Monk horst-pack mesh of 14 × 14 × 14 k points. In addition to this, the equilibrium lattice constant is calculated with different lattice constant.