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HL: Fachverband Halbleiterphysik
HL 48: Topological insulators (HL, jointly with O, TT)
HL 48.12: Vortrag
Mittwoch, 13. März 2013, 12:15–12:30, H16
Bi1−xSbx(110): A non-closed packed surface of a topological insulator — Lucas Barreto, Wendell Simoes da Silva, Malthe Stensgaard, Søren Ulstrup, Marco Bianchi, •Xie-Gang Zhu, Matteo Michiardi, Maciej Dendzik, and Philip Hofmann — Department of Physics and Astronomy, Interdisciplinary Nanoscience Center Århus University, 8000 Århus C, Denmark
Topological insulators are characterised by an insulating bulk band structure, but topological considerations require their surfaces to support gap-less, metallic states. Meanwhile, many examples of such materials have been predicted and found experimentally, but work has concentrated on the closed-packed (111) surface of the topological insulators. Thus, the theoretical picture of an insulating bulk embedded in a metallic surface from all sides of a crystal still needs to be confirmed. Here we present angle-resolved photoemission spectroscopy results from the (110) surface of the topological insulator Bi1−xSbx (x ≈ 0.15). The observed band structure and Fermi contour is in excellent agreement with theoretical predictions and slightly different from the electronic structure of the parent surface Bi(110), in particular around the X1 time-reversal invariant momentum. We argue that the preparation of surfaces different from (111) opens the possibility to tailor the detailed electronic structure and properties of the topological surface states.