Nonlinear impurity screening in semiconductors

Abstract

Nonlinear impurity screening in metals has been widely studied in the literature, and the differences with respect to the linear results have been found to be important. The screening theories available for semiconductors were until very recently obtained in $\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}$ space, and this prevented the study of nonlinear effects. We present here for the first time an investigation of nonlinear impurity screening in a model semiconductor. The Thomas-Fermi theory of dielectric screening, recently developed by one of us, has been used. Nonlinearity effects are found to be of the same order of magnitude as in metals. A remarkable donoracceptor asymmetry is also found.