Reliability of analytical potentials for point-defect simulation in GaAs

Molecular dynamics with analytical potentials is commonly used to obtain the distribution of defects produced by energetic particles in elemental and compound semiconductors. Collision cascades simulated by model-potential molecular dynamics are used to collect statistical data on the defect distribution but the local structure in such materials as GaAs is commonly recognized to be unreliable in comparison to tight-binding or ab initio total energy calculations. These two methods, however, are not practical in simulations of collision cascades because of their large computational workload. In this paper, we analyse the properties of the basic point defects in GaAs as obtained by using different model potentials and compare them to recent ab initio calculations based on the density-functional theory (DFT) in the local-density approximation (LDA). The aim of this work is to evaluate how close the model potential molecular dynamics predictions are to the benchmark DFT results and which model potential most accurately predicts realistic local structures of point defects.