Influence of shape and electric field on electron relaxation and coherent response inquantum-dot molecules

Abstract

We studied the effects of the confinement geometry and of external electric field on theelectron dynamics of spherical and cylindrical double quantum dots. With an effective-massapproach, we found eigenenergies and envelope wave functions for finite confinementnumerically. Using these energy states, we studied the response of the system to electricfield pulses of different intensities, by calculating the density-matrix evolution in thehigh-delocalization regime, considering electron–electron and electron–acoustic phononinteractions, as a function of external DC electric field in the coupling direction. Weobtained suitable conditions for coherent emission from cylindrically shaped dots, while inthe case of spherically shaped dots, the scattering process is faster than the quantum beatoscillation.