Pulsed-gate measurements of the singlet-triplet relaxation time in a two-electron double quantum dot

TL;DR

This paper employs pulsed-gate charge sensing to measure the singlet-triplet relaxation time in a two-electron double quantum dot, revealing a relaxation time of approximately 70 microseconds and enabling the study of spin state dynamics.

Contribution

It introduces a pulsed-gate charge sensing method to accurately measure long singlet-triplet relaxation times in quantum dots, surpassing previous limitations of current measurement techniques.

Findings

Measured singlet-triplet relaxation time of ~70 microseconds.

Determined the (0,2) singlet-triplet splitting.

Demonstrated charge sensing as an effective tool for long relaxation time measurement.

Abstract

A pulsed-gate technique with charge sensing is used to measure the singlet-triplet relaxation time for nearly-degenerate spin states in a two-electron double quantum dot. Transitions from the (1,1) charge occupancy state to the (0,2) state, measured as a function of pulse cycle duration and magnetic field, allow the (1,1) singlet-triplet relaxation time (~70 microseconds) and the (0,2) singlet-triplet splitting to be measured. The use of charge sensing rather than current measurement allows long relaxation times to be readily probed.