Experimental signature of phonon-mediated spin relaxation

TL;DR

This paper experimentally demonstrates how phonons influence spin relaxation in a two-electron quantum dot, showing a non-monotonous dependence of relaxation time on energy splitting and confirming phonon-mediated dissipation.

Contribution

It provides the first experimental evidence of phonon involvement in spin relaxation and introduces a theoretical model explaining the physical mechanism.

Findings

Spin relaxation time varies non-monotonously with energy splitting.

Spin-flip energy is dissipated into the phonon bath.

Experimental confirmation of phonon-mediated spin relaxation.

Abstract

We observe an experimental signature of the role of the phonons in spin relaxation between triplet and singlet states in a two-electron quantum dot. Using both the external magnetic field and the electrostatic confinement potential, we change the singlet-triplet energy splitting from 1.3 meV to zero and observe that the spin relaxation time depends non-monotonously on the energy splitting. A simple theoretical model is derived to capture the underlying physical mechanism. The present experiment confirms that spin-flip energy is dissipated in the phonon bath.