A density-functional based tight-binding approach to GaAs surface reconstructions

A density-functional-based non-orthogonal tight-binding (DF-TB) scheme is used to investigate models for the reconstructions of GaAs(110), (100) and (111) surfaces. The relative stabilities of the competing reconstructions are then determined as a function of the chemical potential, thus simulating a wide range of possible MBE growth conditions. We find a good agreement with recent experiments and ab initio calculations, and establish the validity of the scheme for large-scale applications.