Effects of atomic scale perturbations on Dirac surface states in topological crystalline insulators

Dienstag, 12. Januar 2016 17.15 Uhr Stuttgarter Physikalisches Kolloquium Max-Planck-Institut für Festkörperforschung Max-Planck-Institut für Intelligente Systeme Fachbereich Physik, Universität Stuttgart Hörsaal 2 D5 Stuttgarter Max-Planck-Institute, Heisenbergstraße 1, 70569 Stuttgart-Büsnau Ansprechpartner: Christian Ast E-Mail: [email protected] Telefon: 0711 689-5250 Topological crystalline insulators are recently discovered topological materials where topology and crystal symmetry intertwine to create relativistic massless Dirac electrons. Due to the importance of crystalline symmetry in generating and protecting the Dirac surface states, the topological states in these materials are expected to be highly sensitive to local structure. In this talk I will discuss how local disorder and strain inuence the properties of topological crystalline insulators. In particular I will show that the Dirac point is surprisingly robust against short-range random disorder but sensitive to long-range coherent distortions that break mirror symmetry. I will discuss how different types of strain effect Dirac electrons in momentum space. In particular I will show how the effects of uniaxial strain in this system are counterintuitive and strongly inuenced by the orbital nature of the bands. Effects of atomic scale perturbations on Dirac surface states in topological crystalline insulators Vidya Madhavan University of Illinois, Urbana-Champaign