Quantum point contacts on a GeSn/Ge heterostructure

ORAL

Abstract

GeSn is a promising material for spintronics and quantum technology owing to its strong spin-orbit coupling (SOC). In this work, we present quantized conductance in a quantum point contact (QPC) on a Ge0.94Sn0.06/Ge heterostructure for the first time. The heterostructure was grown by reduce-pressure chemical vapor deposition. Secondary ion mass spectroscopy (SIMS) was used to characterize the Sn fractions in the GeSn alloys. Transmission electron microscopy (TEM) images show high-quality crystallinity of the Ge/GeSn heterostructures. We characterized carrier transport in the GeSn/Ge heterostructure by performing Hall measurements at 1.8 K with the highest mobility of ~ 30,000 cm/V-s. We observed clear quantum Hall plateaus and Shubnikov-de Haas oscillations at large magnetic fields. Under a large magnetic field of 3 T, GeSn-based QPCs show quantized conductance of e2/h, which is attributed to the lift-up of spin degeneracy by Zeeman effects. Under a zero magnetic field, this e2/h quantized plateau can still be observed, which might be attributed to strong SOC or carrier interactions.

*This work was supported by the National Science and Technology Council (NSTC) of Taiwan under Grants of NSTC (110-2112-M-002-043- and 111-2622-8-002-001-) and the Ministry of Education through the Higher Education Sprout Projects (NTU core consortium: 111L892002).

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Presenters

  • Yu-Jui Wu

    • Graduate Institute of Electronics Engineering, National Taiwan University
    • Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan

Authors

  • Tsung-Ying Li

    • Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan

  • Yu-Jui Wu

    • Graduate Institute of Electronics Engineering, National Taiwan University
    • Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan

  • Hung-Yu Tsao

    • Department of Electrical Engineering, National Taiwan University
    • Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan

  • Min-Jui Lin

    • Graduate Institute of Electronics Engineering, National Taiwan University
    • Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan

  • Chia-You Liu

    • Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan

  • Chia-Tse Tai

    • Princeton University

  • Jiun-Yun Li

    • National Taiwan University (NTU)