Electronic and geometrical structures, such as the electric field gradients of [CdM]- (where M was P, As or Sb) acceptor-donor pairs, were studied by using the full-potential Korringa-Kohn-Rostoker Green's function method. In addition, neutral complexes ([CdM]0) and trimers ([CdM2]0) in Si alone were investigated. The electric field gradient depended very sensitively upon the large lattice relaxations which were produced by the defects, and could be explained by using a simple hybridization model. The results of calculations were in good agreement with experimental results, and provided a consistent picture of acceptor-donor complexes in Si and Ge.

Ab initio Study of Acceptor-Donor Complexes in Silicon and Germanium A.Settels, T.Korhonen, N.Papanikolaou, R.Zeller, P.H.Dederichs: Physical Review Letters, 1999, 83[21], 4369-72