Dephasing and interwell transitions in double quantum well heterostructures

TL;DR

This study experimentally investigates quantum interference effects in double quantum well heterostructures, revealing how interwell transitions and dephasing times depend on electron densities and occupancy, with some unexpected independence findings.

Contribution

It provides a detailed experimental analysis of quantum correction to conductivity, specifically measuring interwell transition and dephasing times, and confirms theoretical predictions about their dependencies.

Findings

Interwell transition time $ au_{12}$ resonantly depends on electron density difference.

Dephasing time $ au_$ is unaffected by the occupation of the other well.

Experimental results align with theoretical predictions for quantum well systems.

Abstract

The interference quantum correction to the conductivity in the gated double quantum well Al$_x$Ga$_{1-x}$As/GaAs/Al$_x$Ga$_{1-x}$As structures is studied experimentally. The consistent analysis of the interference induced positive magnetoconductivity allows us to find the interwell transition time $\tau_{12}$ and the electron dephasing time $\tau_\phi$. It has been obtained that $\tau_{12}^{-1}$ resonantly depends on the difference between the electron densities in the wells as predicted theoretically. The dephasing times have been determined under the conditions when one and both quantum wells are occupied. The surprising result is that the $\tau_\phi$ value in the one well does not depend on the occupation of the other one.