Condensed Matter Seminar Series

Quantum Transport in Graphene and Topological Insulator Materials

Helin Cao

Purdue University

Thursday January 17,  11:30 am,  Room 298,  Physics Building

Abstract: Graphene, a single layer of sp2 bonded carbon atoms, is the first free-standing two-dimensional (2D) crystal people have ever synthesized. The wave function of the charge carriers in graphene can be described by massless relativistic Dirac equation, unlike traditional electron gas following Schrödinger’s rule. Recently, it was found that 2D Dirac fermions also exist in the surface of some bulk insulators called 3D topological insulator (TI). More importantly, the surface states (SS) are protected by topological invariants. In this seminar, I will briefly talk about the half integer quantum Hall effect observed in our CVD graphene samples. Then I will focus on quantum transport properties of 3D TI meterials, such as Shubnikov de-Haas oscillations (SdHO) of TI SS in Bi2Te2Se single crystals and bulk quantum Hall effect in highly doped Bi2Se3.