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TT: Fachverband Tiefe Temperaturen

TT 27: Topological Insulators: Mostly Interaction with Magnetic Fields (organized by HL)

TT 27.4: Vortrag

Montag, 31. März 2014, 16:30–16:45, POT 081

Ambipolar quantum Hall effect in strained bulk HgTe — •Cornelius Thienel, Jonas Wiedenmann, Steffen Wiedmann, Christoph Brüne, Christopher Ames, Hartmut Buhmann, and Laurens W. Molenkamp —
Universität Würzburg, Experimentelle Physik III

Strained bulk HgTe has been identified as three-dimensional topological insulator [Phys. Rev. Lett. 106, 126803 (2011)]. A Dirac-specific quantum Hall sequence can unambiguously be demonstrated in transport measurements. Furthermore we identify two subsets of Landau levels that originate from the topological surface states.
Improving the quality of the interfaces hosting the surface states by introducing additional buffer and cap layers to the structure increases the carrier mobilities in the topological states and makes it possible to observe the quantum Hall effect of electrons and holes in a wide gate voltage range. The detection of p-type QHE points towards a suppressed interaction between bulk and surface states.