Interstitial transition atom impurities in silicon: electronic structure and lattice relaxation

Abstract

Both the electronic structure and the `breathing-mode' relaxation for tetrahedral interstitial 3D transition atom impurities in silicon are studied in the local-density approximation. The calculations show that although the interstitial 3d impurities constitute a very large perturbation locally, they interact rather weakly with the surrounding crystal in the sense that they perturb the spatial distribution of electrons on the surrounding atoms only weakly. A special pattern of relaxation is predicted, with an outward relaxation of the first-nearest neighbours and an inward relaxation of the second-nearest neighbours. It is explained in terms of the impurity-induced charge rearrangement.(19 refs)