Controlling Synthetic Spin-Orbit Coupling in a Silicon Quantum Dot with Magnetic Field

TL;DR

This paper demonstrates experimental control of synthetic spin-orbit coupling in silicon quantum dots by analyzing magnetic field orientation effects, revealing a new magnetic field gradient influence and potential qubit optimization strategies.

Contribution

It introduces a method to control synthetic spin-orbit coupling in silicon quantum dots through magnetic field rotation, highlighting the role of in-plane magnetic field gradients.

Findings

Resonance amplitude exhibits nonsinusoidal behavior with magnetic field rotation.

In-plane magnetic field gradient significantly affects synthetic spin-orbit coupling.

Optimal qubit quality factor can be achieved by adjusting magnetic field orientation.

Abstract

Tunable synthetic spin-orbit coupling (s-SOC) is one of the key challenges in various quantum systems, such as ultracold atomic gases, topological superconductors, and semiconductor quantum dots. Here we experimentally demonstrate controlling the s-SOC by investigating the anisotropy of spin-valley resonance in a silicon quantum dot. As we rotate the applied magnetic field in-plane, we find a striking nonsinusoidal behavior of resonance amplitude that distinguishes s-SOC from the intrinsic spin-orbit coupling (i-SOC), and associate this behavior with the previously overlooked in-plane transverse magnetic field gradient. Moreover, by theoretically analyzing the experimentally measured s-SOC field, we predict the quality factor of the spin qubit could be optimized if the orientation of the in-plane magnetic field is rotated away from the traditional working point.