Dresden 2014 – scientific programme

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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.