Phonon-assisted relaxation between hole states in quantum dot molecules

TL;DR

This paper theoretically investigates phonon-assisted relaxation and tunneling of holes in double quantum dots, revealing conditions for long-lived states and the impact of light hole admixture on relaxation rates.

Contribution

It introduces a detailed theoretical model for hole relaxation in quantum dot molecules, highlighting the influence of light hole admixture and tunnel coupling on lifetimes.

Findings

Long-lived hole states occur at specific dot separations due to vanishing tunnel coupling.

Light hole admixture significantly affects hole relaxation rates despite small magnitude.

Relaxation rates are sensitive to quantum dot geometry and material parameters.

Abstract

We study theoretically phonon-assisted relaxation and inelastic tunneling of holes in a double quantum dot. We derive hole states and relaxation rates from kp Hamiltonians and show that there is a finite distance between the dots where lifetimes of hole states are very long which is related to vanishing tunnel coupling. We show also that the light hole admixture to hole states can considerably affect the hole relaxation rates even though its magnitude is very small.