Local polariton states in impure ionic crystals
Abstract
We consider the dynamics of an ionic crystal with a single impurity in the vicinity of the polariton resonance. We show that if the polariton spectrum of the host crystal allows for a gap between polariton branches, the defect gives rise to a novel kind of local states with frequencies within the gap. Despite the atomic size of the impurity we find that new local states are predominated by long-wavelength polaritons. The properties of these states are shown to be different from the properties of the well-known vibrational local states. The difference is due to the singular behavior of the density of states of polaritons near the low-frequency boundary of the polariton gap. Assuming cubic simmetry of the defect site we consider a complete set of the local states arising near the bottom of the polariton gap.
Keywords
Cite
@article{arxiv.cond-mat/9708028,
title = {Local polariton states in impure ionic crystals},
author = {V. S. Podolsky and Lev I. Deych and A. A. Lisyansky},
journal= {arXiv preprint arXiv:cond-mat/9708028},
year = {2009}
}
Comments
10 pages, 3 Postscript figures, to be published in Phys. Rev. B 1998, Vol. 57, No. 3