High-temperature quantum Hall effect in finite gapped HgTe quantum wells

Abstract

We report on the observation of the quantum Hall effect at high temperatures in HgTe quantum wells with a finite band gap and a thickness below and above the critical thickness $d_{\text{c}}$ that separates a conventional semiconductor from a two-dimensional topological insulator. At high carrier concentrations we observe a quantized Hall conductivity up to 60\,K with energy gaps between Landau Levels of the order of 25\,meV, in good agreement with the Landau Level spectrum obtained from $\mathbf{k}\cdot \mathbf{p}$-calculations. Using the scaling approach for the plateau-plateau transition at $\nu =2\to 1$, we find the scaling coefficient $\kappa =0.45\pm 0.04$ to be consistent with the universality of scaling theory and we do not find signs of increased electron-phonon interaction to alter the scaling even at these elevated temperatures. Comparing the high temperature limit of the quantized Hall resistance in HgTe quantum wells with a finite band gap with room temperature experiment in graphene, we find the energy gaps at the break-down of the quantization to exceed the thermal energy by the same order of magnitude.

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Cited by in corpus (5)

• Realistic picture of helical edge states in HgTe quantum wells
• Perspectives of HgTe Topological Insulators for Quantum Hall Metrology
• Phonon-mediated room-temperature quantum Hall transport in graphene
• Interaction dominated transport in 2D conductors: from degenerate to partially-degenerate regime
• HgTe quantum wells for QHE metrology under soft cryomagnetic conditions: permanent magnets and liquid ${}^{4}He$ temperatures