Dresden 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 40: Topological Insulators (jointly with HL, MA)
TT 40.4: Vortrag
Mittwoch, 16. März 2011, 17:30–17:45, HSZ 04
Surface electronic structure and surface state topology of Sb(110). — •Marco Bianchi1, D. Guan1,2, A. Strozecka3, C.H. Voetmann1, J. I. Pasqual3, S. Bao2, and Ph. Hofmann1 — 1Inst. Fysik og Astronomi Aarhus Universitet, Aarhus, Denmark — 2Dep. of Physics, Zheijang University, Hangzhou, China — 3Fachbereich Physik, Freie Universität Berlin, Berlin, Germany
Topological insulators are a recently discovered class of materials where the bulk is insulating while fundamental topological considerations require the surfaces to be metallic. The first experimentally confirmed topological insulator was the intermetallic alloy Bi1−xSbx (0.09 < x < 0.18). This topological insulator phase owes its existence to important changes in the band structure as the two semimetals are alloyed. Theoretical predictions based on the topological character of the bulk electronic structure agree with measurements on the alloy and also predict pure Sb to be a strong topological insulator. On the other hand, the electronic structure of the Bi surfaces, while being very similar to that of the alloy, appears to be consistent with that of a topologically trivial material.
We report on an experimental investigation of the Sb(110) electronic structure combining scanning tunnelling microscopy with angle-resolved photoemission. The topological character of the surface states can be inferred from the number of Fermi level crossings between time-reversal invariant momenta in the surface Brillouin zone. This surface topology is compared to that of Bi(110), Sb(111) and the theoretical predictions.