Phonon-assisted decoherence and tunneling in quantum dot molecules

TL;DR

This paper investigates how phonons influence electron tunneling and decoherence in quantum dot molecules, revealing that phonon-assisted tunneling dominates relaxation processes on a picosecond scale.

Contribution

It introduces a non-perturbative quantum kinetic theory to accurately model electron-phonon interactions, including real and virtual processes, in quantum dot molecules.

Findings

Phonon-assisted tunneling dominates relaxation dynamics.

Relaxation occurs on a picosecond timescale.

Quantum dot occupation depends on energy mismatch.

Abstract

We study the influence of the phonon environment on the electron dynamics in a doped quantum dot molecule. A non-perturbative quantum kinetic theory based on correlation expansion is used in order to describe both diagonal and off-diagonal electron-phonon couplings representing real and virtual processes with relevant acoustic phonons. We show that the relaxation is dominated by phonon-assisted electron tunneling between constituent quantum dots and occurs on a picosecond time scale. The dependence of the time evolution of the quantum dot occupation probabilities on the energy mismatch between the quantum dots is studied in detail.