# Polaron relaxation in a quantum dot due to anharmonic coupling within a mean-field approach - Condensed Matter > Mesoscale and Nanoscale Physics

Abstract: We study the electronic relaxation in a quantum dot within the polaronapproach, by focusing on the {\it reversible} anharmonic decay of longitudinaloptical LO phonons forming the polaron into longitudinal acoustic LAphonons. The coherent coupling between the LO and LA phonons is treated withina mean-field approach. We derive a temperature-dependent inter-level couplingparameter, related to the Gr\-uneisen parameter and the thermal expansioncoefficient, that characterizes an effective decay channel for the electronicor excitonic states. Within this theory, we obtain a characteristicanharmonic decay time of 1ns, 2-3 orders of magnitude longer than previouspredictions based on the Fermi-s Golden Rule. We suggest that coherentrelaxation due to carrier-carrier interaction is an efficient alternative tothe too slow polaron decay.

Author: T. Stauber, M. I. Vasilevskiy

Source: https://arxiv.org/