Direct Real Space Imaging of Quantum Spin Hall Edge States in HgTe Quantum Well

ORAL

Abstract

Microscopic real space imaging of the helical edge states is an important milestone to fully elucidate quantum spin Hall effect as a new state of quantum matter. By employing a unique cryogenic microwave impedance microscope, we directly imaged quantum spin Hall edges in a gapped HgTe quantum well. The edge state size increases monotonically as the Fermi level is tuned from p-type across the Dirac point into n-type. Whereas this result is counter-intuitive within any particle-hole symmetric model, it actually agrees well with the 8-band model of real material. Real space evolution of the edge states shows surprising dependence on the magnetic field which could not be explained by Landau level physics assuming a clean system. Alternative scenarios will be discussed.

*Authors acknowledge financial support from DARPA.

–

Authors

  • Yue Ma

    • Stanford University

  • Worasom Kundhikanjana

    • Stanford University

  • Jing Wang

    • Stanford University

  • Reyes Calvo

    • Stanford University

  • Yongliang Yang

    • Stanford University

  • Keji Lai

    • Stanford University

  • Matthias Baenninger

    • Stanford University

  • Markus K\"onig

    • Stanford University

  • Christopher Ames

    • Universit\"at W\"urzburg

  • Christoph Br\"une

    • Universit\"at W\"urzburg

  • Hartmut Buhmann

    • Universit\"at W\"urzburg

  • Philip Leubner

    • Universit\"at W\"urzburg

  • Qiaochu Tang

    • Shanghai Institute of Microsystem and Information Technology

  • Kun Zhang

    • Shanghai Institute of Microsystem and Information Technology

  • Xinxin Li

    • Shanghai Institute of Microsystem and Information Technology

  • Laurens Molenkamp

    • Universit\"at W\"urzburg

  • Shou-Cheng Zhang

    • Stanford University

  • David Goldhaber-Gordon

    • Stanford University

  • Michael Kelly

    • Stanford University

  • Zhi-Xun Shen

    • Stanford Institute for Materials and Energy Science;Geballe Laboratory for Advanced Materials, Department of Physics and Applied Physics, Stanford, CA
    • Stanford University
    • Department of Applied Physics, Stanford University; SIMES