|Temperature-Induced Topological Phase Transition in HgTe Quantum Wells |
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Ref Arxiv: 1710.06666
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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 Bc is a characteristic of inverted band structure in the quantum well. By measuring the temperature dependence of Bc, we directly extract the critical temperature Tc 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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