Hole-spin qubits in $\mathrm{Ge}$/$\mathrm{Ge}\mathrm{Si}$ heterostructures benefit from the clean environment of epitaxial interfaces and from the intrinsic spin-orbit coupling that enables efficient electrical control, which makes them promising candidates for quantum computation. However, spin-orbit coupling also enhances the sensitivity to electrical disorder, potentially increasing variability. In this work, we perform numerical simulations in a realistic device geometry to quantify the variability of the charge and spin properties of $\mathrm{Ge}$ qubits induced by charge traps at the $\mathrm{Si}\mathrm{Ge}$/oxide interfaces. We show that while the variability of charge properties remains moderate, spin properties ($g$ factors and Rabi frequencies) show significant dispersion. We explore the implications of this variability for large-scale architectures, and provide guidelines to minimize variability both in terms of interface quality requirements and optimal operation strategies.

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• Carrier dynamics
• Quantum information with solid state qubits
• Quantum transport
• Quantum dots
• Semiconductors
• Direct numerical simulations
• Luttinger–Kohn model
• k dot p method