Applicability of Site-Basis Time-Evolution Equation for Thermalization of Exciton States in a Quantum Dot Array

Abstract

We verify the practical applicability of the conventional site-basis time-evolution equation to exciton transfer processes in a quantum-dot array model. The time-evolution equation has proved to work under the rather limited conditions of the zero temperature limit and/or a minimal two-dot system. The computed results dramatically change with the temperature, the number of quantum dots, and the intensity of transition rates between adjacent sites. This is due to the fact that the higher-order perturbation terms, which are neglected in deriving the site-basis equation, have a great influence on the exciton dynamics. We found that the thermal relaxation can be suppressed by controlling the dot size and interdot distance.