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arXiv · 1710.06666

Temperature-induced topological phase transition in HgTe quantum wells

A. M. Kadykov·S. S. Krishtopenko·B. Jouault·W. Desrat·W. Knap·S. Ruffenach·C. Consejo·J. Torres·S. V. Morozov·N. N. Mikhailov·S. A. Dvoretskii·F. Teppe
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Abstract

We report a direct observation of temperature-induced topological phase transition between trivial and topological insulator in 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 electron-like and hole-like subbands. Their crossing at 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.

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A. M. Kadykov, S. S. Krishtopenko, B. Jouault, W. Desrat, W. Knap, S. Ruffenach, C. Consejo, J. Torres, S. V. Morozov, N. N. Mikhailov, S. A. Dvoretskii, F. Teppe. 2018-01-26. Temperature-induced topological phase transition in HgTe quantum wells. https://doi.org/10.1103/physrevlett.120.086401

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