Dirac-Screening Stabilized Surface-State Transport in a Topological Insulator

Please always quote using this URN: urn:nbn:de:bvb:20-opus-118091
  • We report magnetotransport studies on a gated strained HgTe device. This material is a three-dimensional topological insulator and exclusively shows surface-state transport. Remarkably, the Landau-level dispersion and the accuracy of the Hall quantization remain unchanged over a wide density range (3×1011  cm−2<n<2×1012  cm−2). These observations imply that even at large carrier densities, the transport is surface-state dominated, where bulk transport would have been expected to coexist already. Moreover, the density dependence of theWe report magnetotransport studies on a gated strained HgTe device. This material is a three-dimensional topological insulator and exclusively shows surface-state transport. Remarkably, the Landau-level dispersion and the accuracy of the Hall quantization remain unchanged over a wide density range (3×1011  cm−2<n<2×1012  cm−2). These observations imply that even at large carrier densities, the transport is surface-state dominated, where bulk transport would have been expected to coexist already. Moreover, the density dependence of the Dirac-type quantum Hall effect allows us to identify the contributions from the individual surfaces. A k⋅p model can describe the experiments but only when assuming a steep band bending across the regions where the topological surface states are contained. This steep potential originates from the specific screening properties of Dirac systems and causes the gate voltage to influence the position of the Dirac points rather than that of the Fermi level.show moreshow less

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Metadaten
Author: Christoph Brüne, Cornelius Thienel, Michael Stuiber, Jan Böttcher, Hartmut Buhmann, Elena G. Novik, Chao-Xing Liu, Ewelina M. Hankiewicz, Laurens W. Molenkamp
URN:urn:nbn:de:bvb:20-opus-118091
Document Type:Journal article
Faculties:Fakultät für Physik und Astronomie / Institut für Theoretische Physik und Astrophysik
Language:English
Parent Title (English):Physical Review X
ISSN:2160-3308
Year of Completion:2014
Volume:4
Issue:4
Pagenumber:041045
Source:PHYSICAL REVIEW X 4, 041045 (2014). DOI: 10.1103/PhysRevX.4.041045
DOI:https://doi.org/10.1103/PhysRevX.4.041045
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Tag:condensed matter physics; topological insulators
Release Date:2015/08/31
Licence (German):License LogoCC BY: Creative-Commons-Lizenz: Namensnennung