Temperature-Induced Topological Phase Transition in HgTe Quantum Wells

We report a direct observation of temperature-induced topological phase transition between the trivial and topological insulator states in an HgTe quantum well. By using a gated Hall bar device, we measure and represent Landau levels in fan charts at different temperatures, and we follow the tempera...

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Bibliographic Details
Published in:Physical review letters 2018-02, Vol.120 (8), p.086401-086401, Article 086401
Main Authors: Kadykov, A M, Krishtopenko, S S, Jouault, B, Desrat, W, Knap, W, Ruffenach, S, Consejo, C, Torres, J, Morozov, S V, Mikhailov, N N, Dvoretskii, S A, Teppe, F
Format: Article
Language:English
Subjects:
Condensed Matter
Critical temperature
Materials Science
Phase transitions
Physics
Quantum wells
Temperature
Temperature dependence
Transition temperature
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Summary:We report a direct observation of temperature-induced topological phase transition between the trivial and topological insulator states in an HgTe quantum well. By using a gated Hall bar device, we measure and represent Landau levels in fan charts at different temperatures, and we follow the temperature evolution of a peculiar pair of "zero-mode" Landau levels, which split from the edge of electronlike and holelike subbands. Their crossing at a critical magnetic field B_{c} is a characteristic of inverted band structure in the quantum well. By measuring the temperature dependence of B_{c}, we directly extract the critical temperature T_{c} at which the bulk band gap vanishes and the topological phase transition occurs. Above this critical temperature, the opening of a trivial gap is clearly observed.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.120.086401