Mardi 05 juin 2012 à 11h15
Salle 234, Ecole de Physique

Diffusion at the surface of a topological insulator

Pierre Adroguer, Ecole Normale Supérieure de Lyon

Topological insulators (TIs) are a new class of 3-dimensionnal (resp. 2D) materials which exhibit an insulating bulk with conducting surface (resp. edge) states. The surface of 3-dimensionnal topological insulators (3DTI) shares similarities with graphene and provides an experimental realization of a 2D Dirac system with a single (or odd number) of Dirac cones. In this talk, I will present a theory of the diffusion of the surface states of a 3DTI in presence of disorder. After a brief presentation of the recent transport experiments, I will describe the differences between the surface of a 3DTI and graphene, in particular introducing the crucial hexagonal warping of the Dirac cone. I will study the variation of conductivity induced by this hexagonal warping, and I will also present the quantum corrections responsible for both weak anti-localization and universal conductance fluctuations.