Transport in topological insulators

by Patrik Recher (Universitat Wurzburg)

Friday 19 Mar 2010, 14:15 → 15:15 Europe/Zurich

Auditoire Stueckelberg (Univ. de Geneve)

Topological insulators (TIs) are systems that have a bulk gap and surface states which are protected by time-reversal symmetry. I give an introduction into this fascinating new subject highlighting the transport aspect of it. In the two-dimensional TI, the surface is one dimensional and hosts the so called quantum spin Hall effect [1]. Prime examples of such two-dimensional TIs are HgTe quantum wells (QWs). Depending on the thickness of the QW, they can be topologically trivial (no edge states) or topologically non-trivial (helical edge states). However, I show using an effective 4-band model for the QW states, that the topology is also revealed in bulk transport experiments. I will discuss the conductance and shot noise of ballistic bulk transport in HgTe QWs [2]. [1] B.A. Bernevig, T.L. Hughes, and S.C. Zhang, Science 314, 1757 (2006). [2] E.G. Novik, P. Recher, E.M. Hankiewicz, and B. Trauzettel, arXiv:0912.3397.