Effect of Nearest Neighbour Displacement on Donor Energy Levels in Silicon

Abstract

The first principle Pseudo Impurity Theory (PIT) and a variational method are used to estimate the donor binding energies of group V and singly ionised group VI substitutional donors in Si incorporating the contributions from the nearest neighbours into the impurity potential. The impurity core squeezing and the nearest neighbour displacement are realised to be two counterparts of local lattice relaxation. It is found that the inclusion of both these effects by a new scheme proposed by the authors in the present model leads to a more realistic situation.