Magnetic field dependence of Pauli spin blockade: a window into the sources of spin relaxation in silicon quantum dots

TL;DR

This study explores how magnetic fields influence spin relaxation in silicon quantum dots by analyzing leakage current patterns, revealing the roles of spin-orbit interaction and cotunneling in spin blockade phenomena.

Contribution

It provides experimental and theoretical insights into the magnetic field dependence of spin relaxation mechanisms in silicon quantum dots, highlighting the effects of spin-orbit coupling and cotunneling.

Findings

Dip in leakage current at ~40 mT due to spin-orbit relaxation

Peak at ~400 mT attributed to spin-flip cotunneling

Good agreement between theoretical models and experimental data

Abstract

We investigate spin relaxation in a silicon double quantum dot via leakage current through Pauli blockade as a function of interdot detuning and magnetic field. A dip in leakage current as a function of magnetic field on a \sim 40 mT field scale is attributed to spin-orbit mediated spin relaxation. On a larger (\sim 400 mT) field scale, a peak in leakage current is seen in some, but not all, Pauli-blocked transitions, and is attributed to spin-flip cotunneling. Both dip and peak structure show good agreement between theory and experiment.