Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 21: [MA] Joint Session "Topological Insulators I" (jointly with DS, HL, O, TT)
O 21.6: Talk
Monday, March 26, 2012, 19:00–19:15, H 1012
Quantization of conduction and valence band states through adsorption of nonmagnetic impurities on Bi2Se3 — •Marco Bianchi1, Richard Hatch1, Zakaria Abd El-Fattah3, Jianli Mi2, Bo Brummerstedt Iversen2, and Philip Hofmann1 — 1Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark — 2Departamento de Física de Materiales CSIC-UPV/EHU-Materials Physics Center, E-20018 Donostia-San Sebastián, Spain — 3Center for Materials Crystallography, Department of Chemistry, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
Angle-resolved photoemission (ARPES) can give detailed information on the surface electronic structure of materials. Here we present an ARPES study of the adsorption-induced changes in the electronic structure of the topological insulator Bi2Se3(111). Exposure to CO results in strong shifts of the features observed by ARPES. The spectral changes can be explained by a simultaneous confinement of the bulk conduction band and valence band states. This is only possible because of the unusual bulk electronic structure of Bi2Se3. The valence band quantization leads to spectral features which resemble those of a band gap opening at the Dirac point. Similar effects are observed when Rb is adsorbed on the surface. In this case up to seven quantum well states are found in the valence band, both above and below the Dirac point.