Gate control of low-temperature spin dynamics in two-dimensional hole systems

TL;DR

This study explores how gate voltages influence spin dynamics in high-mobility two-dimensional hole systems at very low temperatures, revealing long-lived, localized hole spins and tunable g factors.

Contribution

We demonstrate gate-controlled tuning of the hole g factor and analyze temperature-dependent spin coherence in 2D hole systems, supported by theoretical calculations.

Findings

Hole g factor can be tuned by over 50% with gate voltage.

Long-lived hole spin dynamics are observed at low temperatures.

In-plane localization is key for hole spin coherence.

Abstract

We have investigated spin and carrier dynamics of resident holes in high-mobility two-dimensional hole systems in GaAs/Al$_{0.3}$Ga$_{0.7}$As single quantum wells at temperatures down to 400 mK. Time-resolved Faraday and Kerr rotation, as well as time-resolved photoluminescence spectroscopy are utilized in our study. We observe long-lived hole spin dynamics that are strongly temperature dependent, indicating that in-plane localization is crucial for hole spin coherence. By applying a gate voltage, we are able to tune the observed hole g factor by more than 50 percent. Calculations of the hole g tensor as a function of the applied bias show excellent agreement with our experimental findings.