Counterpropagating topological and quantum Hall edge channels
| Autor: | Saquib Shamim, Pragya Shekhar, Wouter Beugeling, Jan Böttcher, Andreas Budewitz, Julian-Benedikt Mayer, Lukas Lunczer, Ewelina M. Hankiewicz, Hartmut Buhmann, Laurens W. Molenkamp |
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| Rok vydání: | 2021 |
| Předmět: |
Multidisciplinary
Condensed Matter - Mesoscale and Nanoscale Physics Mesoscale and Nanoscale Physics (cond-mat.mes-hall) FOS: Physical sciences General Physics and Astronomy General Chemistry Condensed Matter::Mesoscopic Systems and Quantum Hall Effect General Biochemistry Genetics and Molecular Biology |
| Zdroj: | Nature Communications |
| ISSN: | 2041-1723 |
| Popis: | The survival of the quantum spin Hall edge channels in presence of an external magnetic field has been a subject of experimental and theoretical research. The inversion of Landau levels that accommodates the quantum spin Hall effect is destroyed at a critical magnetic field, and a trivial insulating gap appears in the spectrum for stronger fields. In this work, we report the absence of this transport gap in disordered two dimensional topological insulators in perpendicular magnetic fields of up to 16 T. Instead, we observe that a topological edge channel (from band inversion) coexists with a counterpropagating quantum Hall edge channel for magnetic fields at which the transition to the insulating regime is expected. For larger fields, we observe only the quantum Hall edge channel with transverse resistance close to $h/e^2$. By tuning the disorder using different fabrication processes, we find evidence that this unexpected $\nu=1$ plateau originates from extended quantum Hall edge channels along a continuous network of charge puddles at the edges of the device. Comment: 8+3 pages, 5+2 figures |
| Databáze: | OpenAIRE |
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