Local environment effects on exchange interactions in dilute magnetic semiconductors

Abstract

We discuss local environment effects on exchange interactions in dilute magnetic semiconductors. The effects of local impurity configurations are taken into account by embedding a large cluster into the effective medium calculated by the coherent potential approximation. We find a large discrepancy in calculated exchange interactions by our cluster embedding method and by the Liechtenstein’s method, because in our method the multiple scattering effect between site i and j is fully included. It is also found that the calculated exchange interactions strongly depend on the position of the impurities in the cluster other than site i and j. The average of the configuration dependent interactions approximately converge to the two impurity embedding results.