Observation of topological phase transition by terahertz photoconductivity in HgTe-based transistors

We have found the possibility to probe the magnetic field-driven topological phase transition in HgTe-based transistors by measuring their Terahertz photoconductivity response. At the critical magnetic field to which zero-mode Landau levels cross, we have observed a pronounced photoconductivity peak independent on incident frequency and carrier concentration. Our results pave the way towards terahertz topological field effect transistors. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).