Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 66: Topological Insulators (Joint session of DS, HL, O, and TT, organized by MA)

HL 66.1: Vortrag

Mittwoch, 9. März 2016, 15:00–15:15, H32

Bulk and surface properties of topological insulators from GW calculations. — •Irene Aguilera, Christoph Friedrich, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany.

Many-body calculations within the GW approximation are attracting much attention in the study of topological insulators (TIs). They have shown to be critical both in the one-shot approach [1] (e.g. for the Bi₂Se₃ family) and in a quasiparticle self-consistent (QS) GW method [2] (e.g. for Bi). In both cases, the spin-orbit coupling has to be incorporated directly into the GW self-energy [3]. Within the all-electron FLAPW formalism, we have performed DFT, one-shot GW, and QSGW calculations for well-known TIs. These calculations are very demanding for low-dimensional systems. Therefore, we construct a tight-binding Hamiltonian for the description of topological surface states in a slab geometry. The corresponding parameters are deduced from GW calculations of the bulk. With this approach, we discuss the effects of quasiparticle corrections on the surface states of TIs and on the interaction between bulk and surface states. We show that the GW bulk and surface band structure agrees better to results from photoemission experiments than the DFT one. [1] Phys. Rev. B 87, 121111(R) (2013). [2] Ibid 91, 125129 (2015). [3] Ibid 88, 165136 (2013).

We acknowledge the Virtual Institute for Topological Insulators of the Helmholtz Association.