Dirac-Screening Stabilized Surface-State Transport in a Topological Insulator
- Christoph Brüne
- Cornelius Thienel
- Michael Stuiber
- Jan Böttcher
- Hartmut Buhmann
- Elena G. Novik
- Chao-Xing Liu
- Ewelina M. Hankiewicz
- Laurens W. Molenkamp
DOIAbstract
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 (3×10^{11} cm^{−2}<n<2×10^{12} 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 ...
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