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HL: Fachverband Halbleiterphysik

HL 48: Topological insulators (HL, jointly with O, TT)

HL 48.9: Vortrag

Mittwoch, 13. März 2013, 11:30–11:45, H16

Strained bulk HgTe as a 3D topological insulator — •Cornelius Thienel, Christopher Ames, Philipp Leubner, Christoph Brüne, Hartmut Buhmann, and Laurens W. Molenkamp — Universität Würzburg, Lehrstuhl für experimentelle Physik III

HgTe is a semimetal that has an inverted band structure. We show that strained on CdTe the HgTe opens a bandgap and becomes a 3D topological insulator (TI). By magnetotransport measurements we confirm the existence of a 2D topological state and observe QHE from the surface. An analysis of SdH oszillations allows us to distinguish between two TI surfaces perpendicular to the magnetic field that have different charge carrier densities due to different electrostatic environments. When structuring a top gate on the sample, we are able to match the carrier densities of the surface states and therefore see a sequence of odd integer Hall plateaus, as predicted by Dirac physics.