Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 24: Focused Session: Dirac Fermions in Solid-State Systems (jointly with HL)

TT 24.5: Topical Talk

Dienstag, 12. März 2013, 11:45–12:15, H2

Transport in topological insulators - experiments — •Christoph Brüne — Experimentelle Physik 3, Physikalisches Institut, Universität Würzburg

The prediction and discovery of topological insulators (TIs) has attracted wide interest in the physics community during the past years. The first topological insulator state was predicted and discovered in 2 dimensional systems. I will present our results concerning the quantum spin Hall effect in HgTe quantum wells. The quantum spin Hall effect is the signature state of a 2-dimensional topological insulator.

In 3 dimensions this new state of mater is characterized by conducting Dirac type surface states while the bulk of the material remains insulating. Such surface states have been observed in e.g. Bi2Te3, Bi2Se3 and Sb2Te3. These materials do, however, exhibit large defect densities paired with low carrier mobilities. So far this prevented transport studies in the quantum Hall regime of 3D TIs. Recently, however, we succeeded in using strained bulk HgTe as 3D TI. This enabled us to measure the quantum Hall effect from the 3D TI surface state in transport experiments.