Parameter-free calculations of total energies, interatomic forces and vibrational entropies of defects in semiconductors

Abstract We discuss calculations from first-principles (using the local-density approximation for exchange and correlation) of defect total energies, vibrational modes, internal energies and entropies. Results are presented for the defect-induced distortion field of an arsenic impurity in silicon and for the vibrational entropy of a silicon vacancy. We also discuss the important role of electron and atom chemical potentials, presenting results for the Ga vacancy in the GaAs bulk and at the (111) surface.