Achievement

Topological insulators are materials that are insulators in their interior but behave like metals on their surface. They are especially interesting for fundamental studies of the topological phases of matter, but also for applications to spintronic devices that may be useful for quantum computation. iQuISE Trainee Valla Fatemi has been exploring the electron transport in these materials to better understand the interplay between top and bottom surface-conduction channels, and the unwanted bulk-conductance channel that is due to unintentional doping. His co-authored paper [Phys. Rev. B 84, 233101 (2011)] reports measurements made on charge-density-tunable microdevices patterned from thin films of the topological insulator Bi2Se3. The results obtained from this study are consistent with a model in which channel separation is determined by a competition between the phase coherence time and the surface-to-bulk scattering time.