Abstract

We use first-principles calculations to investigate the atomic geometries and formation energies of vacancies (V-N, V-B) and antisites (B-N, N-B) in cubic boron nitride. We find that V-N and V-B are the most stable defects in p-type and n-type conditions, respectively. They also exhibit intrinsic donor (V-N) and acceptor (V-B) characters, which makes them good candidates for compensation. The equilibrium geometries show large outward breathing relaxations for both vacancies and for B-N, with a slight Jahn-Teller distortion from T-d symmetry. For N-B in neutral and negatives charge states, we find an off-center distortion, inducing a negative-U behavior. (C) 1999 American Institute of Physics. [S0003-6951(99)02120-8].