Theory of 4d transition-metal ions in silicon: total-energies, diffusion, electronic and magnetic properties

Ground-state total-energies, electronic and magnetic properties of the 4d transition-metal ions Zr, Nb, Mo, Tc, Ru, Pd and Ag at the substitutional and tetrahedral interstitial site in crystalline silicon have been calculated using the self-consistent, spin-unrestricted Green-function method. From the comparison with 3d results we find fundamental differences in the site-preference, ground-state symmetries and spins, wave-function locations, local magnetic moments, and deep donor and acceptor levels. The experimentally observed dissimilarity of Cu, Ag and Au impurities in silicon with respect to diffusion and solubility behaviour is explained by our theory. (author) 12 refs., 2 figs., 2 tabs