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Topological insulators (TIs) realize a new quantum state of matter where insulating bulk states coexist with metallic surface states due to a nontrivial Z2 topology of the bulk valence band. I will discuss two prominent examples of novel physics found in TIs for which high-quality thin films grown by molecular beam epitaxy (MBE) are indispensable: I. A striking manifestation of the topological protection revealed in a systematic evolution of the surface conductance as a function of thickness in a series of high-quality Bi2Se3 films. II. The observation of unusual anisotropic magneto-resistance (AMR) and planar Hall effect (PHE) in bulk-insulating (Bi1-xSbx)2Te3 thin films, for which the concentration of Dirac-like surface carriers, and consequently the magnitude of AMR and PHE, can be controlled by electrostatic gating.

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Alexey Taskin, Osaka University
Seminar Room 0.03, ETP
Contact: Achim Rosch