Driven dynamics of a quantum dot electron spin coupled to bath of higher-spin nuclei

TL;DR

This paper develops a theoretical framework for understanding the dynamics of an electron spin in a quantum dot coupled to a nuclear spin bath of arbitrary spin, highlighting the impact of quadrupolar interactions on nuclear polarization and electron spin behavior.

Contribution

It extends the analysis beyond spin-1/2 nuclei to arbitrary spins, incorporating quadrupolar couplings and their effects on nuclear polarization and electron spin dynamics.

Findings

Quadrupolar couplings counteract hyperfine-driven nuclear polarization.

Higher-spin effects significantly influence dynamic nuclear polarization.

Steady-state electron spin evolution reflects the balance between hyperfine and quadrupolar interactions.

Abstract

The interplay of optical driving and hyperfine interaction between an electron confined in a quantum dot and its surrounding nuclear spin environment produces a range of interesting physics such as mode-locking. In this work, we go beyond the ubiquitous spin 1/2 approximation for nuclear spins and present a comprehensive theoretical framework for an optically driven electron spin in a self-assembled quantum dot coupled to a nuclear spin bath of arbitrary spin. Using a dynamical mean-field approach, we compute the nuclear spin polarization distribution with and without the quadrupolar coupling. We find that while hyperfine interactions drive dynamic nuclear polarization and mode-locking, quadrupolar couplings counteract these effects. The tension between these mechanisms is imprinted on the steady-state electron spin evolution, providing a way to measure the importance of quadrupolar interactions in a quantum dot. Our results show that higher-spin effects such as quadrupolar interactions can have a significant impact on the generation of dynamic nuclear polarization and how it influences the electron spin evolution.