Efficient dynamical nuclear polarization in quantum dots: Temperature dependence

TL;DR

This study explores how temperature influences dynamical nuclear polarization in InGaAs quantum dots, revealing increased polarization with rising temperature up to 55K through micro-photoluminescence experiments.

Contribution

It provides new insights into temperature effects on nuclear polarization efficiency in quantum dots, highlighting the underlying mechanisms involved.

Findings

Nuclear polarization increases with temperature from 2K to 55K.

Maximum polarization reaches about 50% at 55K.

Analysis identifies key factors influencing temperature dependence.

Abstract

We investigate in micro-photoluminescence experiments the dynamical nuclear polarization in individual InGaAs quantum dots. Experiments carried out in an applied magnetic field of 2T show that the nuclear polarization achieved through the optical pumping of electron spins is increasing with the sample temperature between 2K and 55K, reaching a maximum of about 50%. Analysing the dependence of the Overhauser shift on the spin polarization of the optically injected electron as a function of temperature enables us to identify the main reasons for this increase.