Electrons on the surface of Bi2Se3 form a topologically-ordered two   dimensional gas with a non-trivial Berry's phase
  The interface between a superconductor and a topological insulator has been proposed to harbor novel quasiparticles that realize physical schemes for fault-tolerant quantum computation. Here, we present high resolution angle-resolved photoemission experimental results, which along with first principles calculations, suggest that the surface-edge states of Bi2Se3 form a topological 2D metal. When magnetic atoms are deposited, the surface tends to lose Kramers' degeneracy and a k-space connection thread between the bulk valence and conduction bands is lost. Our observed states carry a \pi Berry's phase suggesting that although the real materials are often electron doped fully undoped Bi2Se3 would be a Z2 topological insulator at room temperature. 
Y. Xia, L. Wray, D. Qian, D. Hsieh, A. Pal, H. Lin, A. Bansil, D.   Grauer, Y.S. Hor, R.J. Cava, and M.Z. Hasan