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

• Published in: Journal of physics. Condensed matter 2007-08, Vol.19 (34), p.346216-346216 (14)
• Main Authors: Ramirez, H Y, Camacho, A S, Lew Yan Voon, L C
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Quantum dots
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/19/34/346216

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.