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Modelling of planar germanium hole qubits in electric and magnetic fields

ORAL

Abstract

Hole-based spin qubits in strained planar germanium quantum wells have received considerable attention due to their favourable properties and remarkable experimental progress. The sizeable spin-orbit interaction in this structure allows for efficient electric qubit operations while also coupling the qubit to electrical noise.

In this talk we show simulations of a heterostructure hosting these hole spin qubits [1]. We solve the effective mass equations for a realistic heterostructure, provide a set of analytical basis wave functions, and compute the effective g-factor of the heavy-hole ground-state. Our investigations reveal a strong impact of highly excited light hole states located outside the quantum well on the g-factor. We find that sweet spots in out-of-plane magnetic fields are shifted to impractically large electric fields. However, for magnetic fields close to in-plane alignment, sweet spots at low electric fields are recovered. This work will be helpful in understanding and improving coherence of germanium hole spin qubits.

[1] Wang, Scappucci, Veldhorst and Russ, arXiv:2208.04795

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Presenters

  • Maximilian Russ

    Delft University of Technology

Authors

  • Maximilian Russ

    Delft University of Technology

  • Chien-An Wang

    Delft University of Technology, QuTech and Kavli Institute of Nanoscience, QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, The Netherlands

  • Giordano Scappucci

    QuTech and Kavli Institute of Nanoscience, TU Delft, P.O. Box 5046, 2600 GA Delft, The Netherlands, Delft University of Technology, QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, TU Delft QuTech, QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, The Netherlands

  • Menno Veldhorst

    Delft University of Technology, QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, The Netherlands