Tuesday, June 28, 2016

Abstract-Terahertz imaging of Landau levels in HgTe-based topological insulators

Appl. Phys. Lett. 108, 262102 (2016)http://dx.doi.org/10.1063/1.4955018

We report on sub-terahertz photoconductivity under the magnetic field of a two dimensional topologicalinsulator based on HgTe quantum wells. We perform a detailed visualization of Landau levels by means of photoconductivity measured at different gate voltages. This technique allows one to determine a criticalmagnetic field, corresponding to topological phase transition from inverted to normal band structure, even in almost gapless samples. The comparison with realistic calculations of Landau levels reveals a smaller role of bulk inversion asymmetry in HgTe quantum wells than it was assumed previously.

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