Self-consistent impurity calculations in the atomic-spheres approximation

Abstract

We have developed a method for calculating self-consistently the electronic structure around an impurity atom, or an impurity cluster, in a crystalline host. Our method is a Green-function matrix technique based on the linear muffin-tin orbital method in the atomic-spheres approximation. The calculation of the host Green function is extremely efficient and involves diagonalization of a small Hamiltonian matrix for the band structure and subsequent Hilbert transforms. The method is tested for the calculation of one-electron spectra and total energies on systems for which (essentially) exact solutions are known: the Hulth\'en potential, a free H atom, a H atom in jellium, and a Li atom in jellium. The accuracy is better and the computational speed significantly higher than that obtained with the standard Korringa-Kohn-Rostoker Green-function technique.