Effect of strain on hyperfine-induced hole-spin decoherence in quantum dots

TL;DR

This paper theoretically investigates how strain influences the spin decoherence of a heavy-hole in quantum dots, revealing that strain modifies hyperfine interactions and can significantly alter decoherence times.

Contribution

It introduces a model showing how strain affects hyperfine-induced hole-spin decoherence, highlighting the role of conduction band admixture in this process.

Findings

Strain shifts the dependence of decoherence time $T_2$ on external parameters.

External strain causes significant shifts in $T_2$ behavior.

Hyperfine coupling strength is mainly affected by strain through conduction band admixture.

Abstract

We theoretically consider the effect of strain on the spin dynamics of a single heavy-hole (HH) confined to a self-assembled quantum dot and interacting with the surrounding nuclei via hyperfine interaction. Confinement and strain hybridize the HH states, which show an exponential decay for a narrowed nuclear spin bath. For different strain configurations within the dot, the dependence of the spin decoherence time $T_2$ on external parameters is shifted and the non-monotonic dependence of the peak is altered. Application of external strain yields considerable shifts in the dependence of $T_2$ on external parameters. We find that external strain affects mostly the effective hyperfine coupling strength of the conduction band (CB), indicating that the CB admixture of the hybridized HH states plays a crucial role in the sensitivity of $T_2$ on strain.