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MA: Fachverband Magnetismus
MA 55: Poster II
MA 55.112: Poster
Friday, April 4, 2014, 10:30–13:30, P2
Ab-initio calculations and ARPES measurements for the bulk topological insulators Bi2Se3 and Bi2Te3 — •I. Aguilera1, I.A. Nechaev2, M. Michiardi3, R.C. Hatch3, M. Bianchi3, D. Guan3, C. Friedrich1, J.L. Mi3, B.B. Iversen3, V.E. de Carvalho4, L.O. Ladeira4, N.G. Teixeira4, E.A. Soares4, Ph. Hofmann3, E.V. Chulkov5, and S. Blügel1 — 1Forschungszentrum Jülich — 2Tomsk State University — 3Aarhus University — 4Universidade Federal de Minas Gerais — 5Universidad del Pais Vasco
Most theoretical studies of topological insulators were so far based on model Hamiltonians, parameter-dependent tight-binding descriptions, and density functional theory employing either the local-density (LDA) or generalized gradient approximation. But recently, many-body calculations within the GW approximation were attracting much attention in the study of these materials. In this work, we have performed LDA and GW calculations for bulk Bi2Se3 and Bi2Te3 within the all-electron FLAPW formalism. We present a detailed comparison of the calculations to angle-resolved photoemission spectroscopy (ARPES) data obtained over a wide range of photon energies. We find that the GW corrected bands agree much better with experiment than the LDA bands. In particular, the characteristic “camelback” shape of the valence band around the Γ point flattens in GW in the case of Bi2Te3 and disappears for Bi2Se3, in accordance with experiments.
Work is supported by the Helmholtz Virtual Institute for Topological Insulators (VITI) and the Alexander von Humboldt Foundation.