Trapping of lattice polarons by impurities

Hague, J. P.; Kornilovitch, P. E. and Alexandrov, A.S. (2008). Trapping of lattice polarons by impurities. Physical Review B, 78(9), article no. 092302.

DOI: https://doi.org/10.1103/PhysRevB.78.092302

Abstract

We consider the effects of impurities on polarons in three dimensions using a continuous time quantum Monte Carlo algorithm. An exact treatment of the phonon degrees of freedom leads to a very efficient algorithm, and we are able to compute the polaron dynamics on an infinite lattice by developing an auxiliary weighting scheme. The magnitude of the impurity potential, the electron-phonon coupling, and the phonon frequency are varied. We determine the magnitude of the impurity potential required for polaron trapping. For small electron-phonon coupling the number of phonons increases dramatically on trapping combined with a sharp decrease in kinetic energy. The polaron binding diagram is computed, showing that intermediate-coupling low-phonon-frequency polarons are localized by exceptionally small impurities.