Modeling few-hole quantum dots in Ge/SiGe: g-factors and qubit properties

We present a detailed numerical model for single- and few-hole quantum dots in Ge/SiGe qubit devices. The impact of the finite confinement, split-off band, inter-hole interactions, and image charges on the energy level structure, g-tensors, electric dipole spin resonance (EDSR) Rabi frequencies, and dephasing rates are assessed. Our model is compared to recent magnetospectroscopy experiments on a few-hole device in which a simpler model was able to reproduce results for the first shell, but not the higher ones. We find that accounting for these additional effects better rationalize prior experimental observations and elaborate on their relative importance. We also consider the potential utility of higher filling Ge hole quantum dots for qubit applications.