Transport in topological insulator films*

The prediction and the subsequent confirmation of topological insulators is one of the most exciting discoveries in condensed matter physics. In the transport study of topological insulator films, we demonstrate that an excellent agreement between theory and experiment is achieved when both disorder and interaction are taken into account. In addition, measurements under an in-plane magnetic field, along and perpendicular to the bias current show opposite magnetoersistance. Furthermore, Bi2Se3 topological insulator thin films contacted by superconducting (In, Al and W) electrodes show an abrupt resistance upturn when the electrodes become superconducting. Concomitant with the upturn in resistance, there is a significant weakening of the superconductivity of the electrodes.