Gate-based spin readout of hole quantum dots with site-dependent $g-$factors

TL;DR

This paper demonstrates gate-based reflectometry for spin readout in hole quantum dots, revealing site-dependent g-factors and providing a method to characterize local spin properties in silicon-based qubits.

Contribution

It introduces a novel experimental approach to measure site-dependent g-factors in hole quantum dots using gate-based reflectometry, supported by analytical and numerical modeling.

Findings

Site-dependent g-factors are detectable via reflectometry signals.

Analytical modeling accurately describes the physical parameters.

Numerical calculations suggest a practical method for local g-factor extraction.

Abstract

The rapid progress of hole spin qubits in group IV semiconductors has been driven by their potential for scalability. This is owed to the compatibility with industrial manufacturing standards, as well as the ease of operation and addressability via all-electric drives. However, owing to a strong spin-orbit interaction, these systems present variability and anisotropy in key qubit control parameters such as the Land\'e $g-$factor, requiring careful characterisation for reliable qubit operation. Here, we experimentally investigate a hole double quantum dot in silicon by carrying out spin readout with gate-based reflectometry. We show that characteristic features in the reflected phase signal arising from magneto-spectroscopy convey information on site-dependent $g-$factors in the two dots. Using analytical modeling, we extract the physical parameters of our system and, through numerical calculations, we extend the results to point out the prospect of conveniently extracting information about the local $g-$factors from reflectometry measurements.