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Interplay of Dirac Nodes and Volkov-Pankratov Surface States in Compressively Strained HgTe

ORAL

Abstract

With the advent of topological materials, the Weyl fermion, a massless particle once proposed to describe neutrinos, can now be investigated in condensed matter systems as Weyl semi-metals, and their close cousins Dirac semi-metals. The HgTe material system, as a prototypical topological insulator for transport studies, is ideally suited, as the tunability of the details of its band structure through strain engineering, and its Fermi level by gating provide unparalleled control for the investigation of Weyl/Dirac semi-metals [1].
We can clearly disentangle surface and bulk contributions by using gate voltage to tune the Fermi energy precisely to the Weyl/Dirac nodes and thus convincingly identify the chiral anomaly. We find no evedince for Fermi-arcs, but topological surface states, that are responsible for the transport in the electron regime. These states are created by the same band inversion leading to the formation of the Dirac/Weyl nodes, and therefore must always be present. Additionally, in the hole regime surface states induced by the electric field, so called massive Volkov-Pankratov states [2, 3], are observed.

[1] D. M. Mahler, et al. Phys. Rev. X 9, 031034 (2019)
[2] B. A. Volkov and O. A. Pankratov, JETP Lett. 42, 4 (1985)
[3] A. Inhofer, et al. PRB 96, 195104 (2017)

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Presenters

  • David Mahler

    University of Wurzburg

Authors

  • David Mahler

    University of Wurzburg

  • Julian-Benedikt Mayer

    University of Wurzburg

  • Philipp Leubner

    University of Wurzburg, Eindhoven University of Technology

  • Lukas Lunczer

    University of Wurzburg

  • Domenico Di Sante

    University of Wurzburg, University of Wuerzburg (Germany), Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Institut für Theoretische Physik und Astrophysik, University of Würzburg

  • Giorgio Sangiovanni

    University of Wurzburg, University of Wuerzburg (Germany), Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, University of Würzburg, Universitaet Wuerzburg, Institut fuer Theoretische Physik und Astrophysik and Wuerzburg-Dresden Cluster of Excellence ct.qmat

  • Ronny Thomale

    University of Wurzburg, Institute for Theoretical Physics, University of Wuerzburg, Theoretical physics I, University of Wuerzburg, University of Wuerzburg, Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Physics department, University of Wuerzburg, Institut für Theoretische Physik und Astrophysik, University of Würzburg, Institute for Theoretical Physics and Astrophysics, University of Wurzburg

  • Ewelina M Hankiewicz

    University of Wurzburg, Universität Würzburg, Germany

  • Hartmut Buhmann

    University of Wurzburg

  • Charles Gould

    University of Wurzburg

  • Laurens W Molenkamp

    University of Wurzburg