Decay and persistence of spatial coherence during phonon-assisted relaxation in double quantum dots

TL;DR

This paper theoretically investigates how spatial coherence evolves during phonon-assisted relaxation in double quantum dots, revealing conditions for coherence transfer and its dependence on system parameters.

Contribution

It introduces a novel mechanism for coherence transfer in uncoupled quantum dots via phonon interactions, highlighting the role of degeneracy and system parameters.

Findings

Spatial coherence can transfer to the ground state under specific degeneracy conditions.

The amount of coherence depends on inter-dot distance and temperature.

Carrier-phonon dynamics influence coherence in coupled quantum dot systems.

Abstract

We present a theoretical study of the evolution of spatial coherence during relaxation between delocalized exciton states in a pair of vertically stacked semiconductor quantum dots coupled to acoustic phonons. We show that spatial coherence can be transferred to the ground state even in a system of uncoupled non-identical quantum dots if a particular kind of degeneracy between the inter-level energy splittings is present. The phonon-assisted mechanism of coherence transfer leads to a dependence of the amount of the resulting coherence on the inter-dot distance and temperature. We analyze also the impact of carrier-phonon dynamics on a coupled system, where spatial coherence is present in the delocalized ground state.