Temperature dependence of electron-spin relaxation in a single InAs quantum dot at zero applied magnetic field

TL;DR

This study investigates how electron-spin relaxation in a single InAs quantum dot varies with temperature, revealing two regimes and proposing a phonon scattering model for high-temperature behavior.

Contribution

It provides the first detailed analysis of temperature-dependent electron-spin relaxation in a single InAs quantum dot at zero magnetic field, introducing a phonon scattering model.

Findings

Spin relaxation is temperature-independent below 50 K due to nuclear spin effects.

Above 50 K, spin relaxation accelerates with temperature.

A two LO phonon scattering model explains high-temperature relaxation.

Abstract

The temperature-dependent electron spin relaxation of positively charged excitons in a single InAs quantum dot (QD) was measured by time-resolved photoluminescence spectroscopy at zero applied magnetic fields. The experimental results show that the electron-spin relaxation is clearly divided into two different temperature regimes: (i) T < 50 K, spin relaxation depends on the dynamical nuclear spin polarization (DNSP) and is approximately temperature-independent, as predicted by Merkulov et al. (ii) T > about 50 K, spin relaxation speeds up with increasing temperature. A model of two LO phonon scattering process coupled with hyperfine interaction is proposed to account for the accelerated electron spin relaxation at higher temperatures.