Total-energy calculations of the structural properties of the group-V element arsenic

Abstract
We report self-consistent density-functional calculations of the total energy of arsenic as a function of volume in the simple-cubic and the distorted α-arsenic (A7) structures. We find the stable structure to be the A7, with parameters which are close to experiment at zero pressure. The simple-cubic structure is found not to be a minimum in the total energy at any pressure because of an instability to A7-symmetry phonon displacements of the atoms. For the stable structure the calculated electronic band structure is reported and shown to have the semimetallic character known for As.