Electronic relaxation in embedded few-atom systems

Abstract

We consider electronic relaxation in a small sample embedded in a host material that is held at thermal equilibrium. In our model description, the coupling of the sample electrons with the surrounding environment is mediated by the local vibrational modes in the sample region. Due to their coupling with the environment, these modes have a finite lifetime. The evolution of the electronic configuration with time is determined by studying the evolution of a density matrix, which is restricted to the electronic and vibrational degrees of freedom in the sample region. The thermalization of an excited electron is described using an iterative procedure. We present results for a single electron in a loop structure, where the electrons are coupled either to an ensemble of decoupled harmonic oscillators or to the acoustical phonons of the loop.