Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 9: Transport: Topological Insulators 1 (jointly with TT, MA)

HL 9.7: Talk

Monday, March 26, 2012, 11:00–11:15, H 3010

Surface flat bands in gapless topological phases — •Andreas Schnyder — Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany

In this talk we discuss a classification of Fermi surfaces, Fermi lines and Fermi points, as well as nodal lines and nodal points in superconductors in terms of discrete symmetries and Fermi surface codimension. By use of a bulk-boundary correspondence, we determine the types of topologically protected zero-energy states that appear at the boundary of these gapless topological systems. As concrete examples we examine the polar state of 3He, the nodal non-centrosymmetric superconductor Li2Pt3B, and the ferromagnetic superconductor URhGe. For the latter two systems, we examine the signatures of the protected surface states in tunneling-conductance measurements and in Fourier transformed scanning tunneling spectra. Furthermore, we study the appearance of gapless modes located on topological defects in gapless topological phases.