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 dc 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 k· p-calculations. Using the scaling approach for the plateau-plateau transition at ν=2→ 1, we find the scaling coefficient κ =0.45 ± 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.