Discovery of spin-textured single-Dirac-cone pi-Berry's phase Topological Insulator states in Bi2Se3, Bi2Te3 and Sb2Te3 and related new materials

The topological insulator is a fundamentally new state of quantum matter that exhibits exotic quantum-Hall-like behavior even in the absence of an applied magnetic field. In this talk, I will present new results on the topological insulator in Bi1-xSbx beyond Ref-[1,2], and then report our discovery and findings of a new generation of topological insulators with a single spin-helical surface Dirac cone that can be gated by chemical tuning of the surface [3,4,5]. A method would be discussed how superconducting and magnetic interactions [6] can be realized within the topological matrix. [1] ``A topological Dirac insulator in a quantum spin Hall phase'', D. Hsieh et al., Nature 452, 970 (2008). [2] ``Observation of unconventional quantum spin textures in topological insulators'', D. Hsieh et al., Science 323, 919 (2009). [3] ``Observation of a large-gap topologicalinsulator class with a single Dirac cone on the surface'', Y. Xia et al., Nature Phys. 5, 398 (2009). [4] D. Hsieh et al., Phys. Rev. Lett., 103, 146401 (2009). [5] ``A tunable topological insulator in the spin helical Dirac transport regime'', D. Hsieh et al., Nature 460, 1101 (2009). [6] Preprint (2009).