Evidence for electron-electron interaction in topological insulator thin films (2011-06-29)
Although there has been a flurry of work on the so-called topological insulators, the role of interaction has largely been neglected so far. To enhance the relative contribution of the surface states to transport, we consider in our work single crystal thin films of Bi2Se3, grown by molecular beam epitaxy, both with and without Pb doping. Our ARPES data demonstrate topological surface states with a Fermi level lying inside the bulk band gap. Transport data show weak anti-localization behavior, as expected for a 2D system, but a detailed analysis shows that the temperature and magnetic field dependences of resistance cannot be reconciled in a theory that neglects inter-electron interactions. We demonstrate that an excellent agreement between theory and experiment is achieved when the interaction is taken into account. These results add a new dimension to the physics of topological insulators, setting the stage for further investigations in this direction.
This work done by Prof. Jian Wang and collaborators is published in PRB: Phys. Rev. B 83, 245438 (2011).
Figure: (Left) Angle Resolved Photoemission Spectropy (ARPES) data; (Right) Transport measurement results at low temperatures.