On the Electronic Polarization Effect on Excitons in Insulators

Abstract

The electronic polaron model and a rapidly convergent expansion in second-order perturbation theory are used to study the effect of electronic polarization on the states of excitons in insulators. The effective interaction obtained consists of two parts: a direct interaction, which contains the usual self-energy, mass correction, and Lamb shift; and an exchange (screening) interaction, the leading terms of which are closely related to the Haken–Schottky potential and a term obtained by Shindo. Our results are applied (a) to calculate exciton binding energies and (b) to investigate the electronic polarization effect on excitons for rare gas solids, making use of a variational technique. As expected, deep levels are affected less by polarization effects than the shallower levels.