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

Abstract

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