Temperature induced spin coherence dissipation in quantum dots

TL;DR

This study investigates how increasing temperature affects electron spin coherence in quantum dots, revealing a sharp decline in coherence time above 20 K likely due to elastic phonon-related interactions.

Contribution

It provides new insights into temperature-induced spin decoherence mechanisms in quantum dots, highlighting effects beyond phonon inelastic scattering.

Findings

Spin coherence time remains microseconds below 20 K

Sharp drop in T2 above 20 K to nanoseconds

Elastic phonon-mediated fluctuations may cause decoherence

Abstract

The temperature dependence of electron spin coherence in singly negatively charged (In,Ga)As/GaAs quantum dots is studied by time-resolved Faraday rotation. The decoherence time T2 is constant on a microsecond scale for temperatures below 20 K, for higher temperatures it shows a surprisingly sharp drop into the nanoseconds range. The decrease cannot be explained through inelastic scattering with phonons, and may be related with elastic scattering due to phonon-mediated fluctuations of the hyperfine interaction.