Probing g-tensor reproducibility and spin-orbit effects in planar silicon hole quantum dots

TL;DR

This study investigates the g-tensor and spin-orbit effects in planar silicon hole quantum dots, revealing anisotropies and the dominant surface Dresselhaus mechanism, with implications for spin-qubit device optimization.

Contribution

It provides the first detailed analysis of g-tensor reproducibility and spin-orbit coupling mechanisms in planar silicon hole quantum dots across different hole occupations.

Findings

g-tensor and spin-leakage current are highly anisotropic

Surface Dresselhaus is identified as the dominant spin-orbit mechanism

g-factor difference correlates with spin-leakage current anisotropy

Abstract

In this work, we probe the sensitivity of hole-spin properties to hole occupation number in a planar silicon double-quantum dot device fabricated on a 300 mm integrated platform. Using DC transport measurements, we investigate the g-tensor and spin-relaxation induced leakage current within the Pauli spin-blockade regime as a function of magnetic-field orientation at three different hole occupation numbers. We find the g-tensor and spin-leakage current to be highly anisotropic due to light-hole/heavy-hole mixing and spin-orbit mixing, but discover the anisotropies to be relatively insensitive to the dot hole number. Furthermore, we extract the dominant inter-dot spin-orbit coupling mechanism as surface Dresselhaus, with an in-plane orientation parallel to transport and magnitude $\boldsymbol{t_{SO}}$ $\approx$ 300 neV. Finally, we observe a strong correlation between the g-factor difference ($\delta$$\boldsymbol{g}$) between each dot and the spin-leakage current anisotropy, as a result of $\delta$$\boldsymbol{g}$ providing an additional spin-relaxation pathway, and should be considered. ]Our findings indicate that hole-spin devices are not as sensitive to precise operating conditions as anticipated. This has important implications optimizing spin control and readout based on magnetic-field direction, together with tuning large arrays of QDs as spin-qubits.