Electrical control of a spin qubit in InSb nanowire quantum dots: strongly suppressed spin relaxation in high magnetic field

TL;DR

This study explores how gating potential and magnetic field influence phonon-induced spin relaxation and qubit operation speed in InSb nanowire quantum dots, revealing suppression of relaxation at high magnetic fields and specific gating conditions.

Contribution

It demonstrates that high magnetic fields and confinement can significantly suppress spin relaxation in InSb nanowire spin qubits, highlighting the importance of gating potential for qubit operation optimization.

Findings

Spin relaxation is suppressed at high magnetic fields due to confinement effects.

Electron-phonon scattering dominates in high g-factor materials like InSb.

Optimal gating potential enhances qubit operation during its lifetime.

Abstract

In this paper, we investigate the impact of gating potential and magnetic field on phonon induced spin relaxation rate and the speed of the electrically driven single-qubit operations inside the InSb nanowire spin qubit. We show that a strong $g$ factor and high magnetic field strength lead to the prevailing influence of electron-phonon scattering due to deformation potential, considered irrelevant for materials with a weak $g$ factor, like GaAs or Si/SiGe. In this regime, we find that spin relaxation between qubit states is significantly suppressed due to the confinement perpendicular to the nanowire axis. We also find that maximization of the number of single-qubit operations that can be performed during the lifetime of the spin qubit requires single quantum dot gating potential.