Johnpierre Paglione, University of Maryland
September 30, 2014

Topological insulator (TI) materials, with metallic boundary states protected against time-reversal-invariant perturbations, are a new and exciting avenue for realizing exotic quantum states of matter with strong potential for new and advanced technologies. As usual, predictions of new three-dimensional TI materials are widespread but obtaining conclusive proof of the existence of non-trivial TI states continues to be a challenge. To date, the majority of effort has focused on a family of layered bismuth-based compounds now regarded as the archetype TI material. However, these materials are in reality good conducting metals with bulk carriers, requiring advanced device and measurement techniques to dig out the intrinsic topological state properties. I will discuss our efforts to advance this state of affairs by improving on materials quality and diversity, focusing on both non-interacting Bi2Se3 and the "new" mixed-valence topological Kondo insulator SmB6. Using unique synthesis techniques as well as careful low-temperature experiments, we have new convincing evidence and characterization of the topologically non-trivial surface states in these materials.

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