Spin lifetime and charge noise in hot silicon quantum dot qubits

TL;DR

This study explores how magnetic field, temperature, and charge noise affect spin lifetime in silicon quantum dots, revealing key relaxation mechanisms and promising qubit operation at higher temperatures.

Contribution

It provides a comprehensive model of spin relaxation considering spin-valley mixing and noise sources, advancing understanding of silicon qubit coherence.

Findings

Spin lifetime reaches 2.8 ms at 1.1 K.

Johnson noise and two-phonon processes limit relaxation.

Charge noise increases linearly with temperature up to 4 K.

Abstract

We investigate the magnetic field and temperature dependence of the single-electron spin lifetime in silicon quantum dots and find a lifetime of 2.8 ms at a temperature of 1.1 K. We develop a model based on spin-valley mixing and find that Johnson noise and two-phonon processes limit relaxation at low and high temperature respectively. We also investigate the effect of temperature on charge noise and find a linear dependence up to 4 K. These results contribute to the understanding of relaxation in silicon quantum dots and are promising for qubit operation at elevated temperatures.