Electrically Tuneable Variability in Germanium Hole Spin Qubits

Fuente: arXiv
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Main Authors: Valvo, Edmondo, Jakob, Michele, Del Vecchio, Patrick, Rimbach-Russ, Maximilian, Bosco, Stefano
Format: Preprint
Published: 2025
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author Valvo, Edmondo
Jakob, Michele
Del Vecchio, Patrick
Rimbach-Russ, Maximilian
Bosco, Stefano
author_facet Valvo, Edmondo
Jakob, Michele
Del Vecchio, Patrick
Rimbach-Russ, Maximilian
Bosco, Stefano
contents Hole spin qubits in planar germanium heterostructures are frontrunners for scalable semiconductor quantum computing. However, their current performance is mostly limited by large dot-to-dot variability that leads to uncontrolled qubit energies and random tilts in the spin quantization axis. Here, we propose a systematic and local method to engineer the spin qubit response by imprinting a controlled anisotropy in the quantum dot confinement, enabling on-demand electric g-tensor control. In particular, we find that both the quantum-dot size and asymmetry allow electrical tuning of the g-tensor and significantly suppress magnitude and angular variability of the spin response for selected magnetic field directions. We confirm this behavior by analyzing single-disorder realizations and statistical ensembles in state-of-the-art strained and unstrained germanium channels, showing that the latter provides an optimal path for $g$-tensor engineering. Our results provide practical design principles for on-demand control of the spin response and mitigating variability, paving the way towards large-scale germanium-based quantum computers.
format Preprint
id arxiv_https___arxiv_org_abs_2512_12702
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Electrically Tuneable Variability in Germanium Hole Spin Qubits
Valvo, Edmondo
Jakob, Michele
Del Vecchio, Patrick
Rimbach-Russ, Maximilian
Bosco, Stefano
Mesoscale and Nanoscale Physics
Quantum Physics
Hole spin qubits in planar germanium heterostructures are frontrunners for scalable semiconductor quantum computing. However, their current performance is mostly limited by large dot-to-dot variability that leads to uncontrolled qubit energies and random tilts in the spin quantization axis. Here, we propose a systematic and local method to engineer the spin qubit response by imprinting a controlled anisotropy in the quantum dot confinement, enabling on-demand electric g-tensor control. In particular, we find that both the quantum-dot size and asymmetry allow electrical tuning of the g-tensor and significantly suppress magnitude and angular variability of the spin response for selected magnetic field directions. We confirm this behavior by analyzing single-disorder realizations and statistical ensembles in state-of-the-art strained and unstrained germanium channels, showing that the latter provides an optimal path for $g$-tensor engineering. Our results provide practical design principles for on-demand control of the spin response and mitigating variability, paving the way towards large-scale germanium-based quantum computers.
title Electrically Tuneable Variability in Germanium Hole Spin Qubits
topic Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2512.12702