This work presents a cross-material, design-oriented framework for electrically tunable spin–orbit qubits, focusing on realistic operating windows for four key semiconductor platforms: GaAs, InAs, InSb, and SiGe. Building on validated two-band models, we introduce a unified set of energy-based figures of merit—qubit gap (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\Delta _{q}\)</EquationSource> </InlineEquation>), isolation energy (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\Delta _{iso}\)</EquationSource> </InlineEquation>), and anharmonicity (A)–to assess qubit performance and leakage suppression within experimentally achievable magnetic fields (GaAs/SiGe below 2 T; InAs/InSb up to 5 T). The framework reveals explicit trade-offs between controllability and fidelity by mapping the combined effects of Rashba (<InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\alpha \)</EquationSource> </InlineEquation>) and Dresselhaus (<InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\beta \)</EquationSource> </InlineEquation>) spin–orbit couplings, vertical electric field F, and valley splitting parameters (<InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\Delta _v\)</EquationSource> </InlineEquation>, <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(t_v\)</EquationSource> </InlineEquation>). Results highlight that InAs offers strong intrinsic tunability with minimal leakage, while GaAs requires careful co-tuning of <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(\alpha \)</EquationSource> </InlineEquation> and <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(\beta \)</EquationSource> </InlineEquation>, and SiGe performance depends critically on maximizing <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(\Delta _v\)</EquationSource> </InlineEquation> and minimizing <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\(t_v\)</EquationSource> </InlineEquation>. These findings provide practical guidelines for material selection and device optimization, bridging theoretical modeling with experimental implementation for next-generation semiconductor qubits.

Cross-material operating windows of electric-field programmable Rashba qubits for frequency allocation and leakage control

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2026年4月20日

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M. A. M. Sharaf

摘要

This work presents a cross-material, design-oriented framework for electrically tunable spin–orbit qubits, focusing on realistic operating windows for four key semiconductor platforms: GaAs, InAs, InSb, and SiGe. Building on validated two-band models, we introduce a unified set of energy-based figures of merit—qubit gap ( \(\Delta _{q}\) ), isolation energy ( \(\Delta _{iso}\) ), and anharmonicity (A)–to assess qubit performance and leakage suppression within experimentally achievable magnetic fields (GaAs/SiGe below 2 T; InAs/InSb up to 5 T). The framework reveals explicit trade-offs between controllability and fidelity by mapping the combined effects of Rashba ( \(\alpha \) ) and Dresselhaus ( \(\beta \) ) spin–orbit couplings, vertical electric field F, and valley splitting parameters ( \(\Delta _v\) , \(t_v\) ). Results highlight that InAs offers strong intrinsic tunability with minimal leakage, while GaAs requires careful co-tuning of \(\alpha \) and \(\beta \) , and SiGe performance depends critically on maximizing \(\Delta _v\) and minimizing \(t_v\) . These findings provide practical guidelines for material selection and device optimization, bridging theoretical modeling with experimental implementation for next-generation semiconductor qubits.