We present a theoretical prediction of a new mechanism for carrier population inversion in semiconductors under an applied electric field. The mechanism is originated from a coherent capture-emission type inelastic scattering of resonant states. We support our theory with concrete calculations for shallow acceptor resonant states in strained p-Ge where a lasing in THz frequency region has been recently observed.
@article{arxiv.cond-mat/9811358,
title = {Population Inversion Induced by Resonant States in Semiconductors},
author = {M. A. Odnoblyudov and I. N. Yassievich and M. S. Kagan and Yu. M. Galperin and X. H. Wang and K. A. Chao},
journal= {arXiv preprint arXiv:cond-mat/9811358},
year = {2009}
}