Linear-combination-of-atomic-orbitals, self-consistent-field method for the determination of the electronic structure of deep levels in semiconductors

Abstract

A linear-combination-of-atomic-orbitals (-molecular-orbitals), self-consistent-field method for the treatment of the electronic configuration of deep levels in semiconductors is described. It is applied to clusters of 17 and 47 carbon atoms and to clusters containing a substitutional (boron or nitrogen) impurity. It is shown that self-consistency brings large improvements over a noniterative procedure, such as the extended Hückel theory. We also propose a method to calculate the total energy of the cluster, necessary to take into account the lattice distortion that occurs around the defect. A detailed discussion of all the terms that have to be taken into account in the evaluation of the energy is made. Justifications of the validity of this calculation are given for 17 and 47 carbon atoms clusters, and the Jahn-Teller distortion associated with substitutional nitrogen in a 47 atoms cluster is determined.