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O: Fachverband Oberflächenphysik
O 101: Topology and Symmetry-protected Materials (joint session O/TT)
O 101.5: Vortrag
Freitag, 21. März 2025, 11:30–11:45, H25
Probing the Electronic Structure at the Boundary of Topological Insulators in the Bi2Se3 Family by Combined STM and AFM — •Christoph S. Setescak1, Irene Aguilera2, Adrian Weindl1, Matthias Kronseder1, Andrea Donarini1, and Franz J. Giessibl1 — 1University of Regensburg, Regensburg, Germany — 2University of Amsterdam and European Theoretical Spectroscopy Facility (ETSF), Amsterdam, The Netherlands
We develop a numerical scheme for the calculation of tunneling current I and differential conductance dI/dV of metal and CO terminated STM tips on the topological insulators Bi2Se3, Bi2Te2Se and Bi2Te3 and find excellent agreement with experiment. The calculation is an application of Chen's derivative rule, whereby the Bloch functions are obtained from Wannier interpolated tightbinding Hamiltonians and maximally localized Wannier functions from first-principle DFT+GW calculations. We observe signatures of the topological boundary modes, their hybridization with bulk bands, Van Hove singularities of the bulk bands and characterize the orbital character of these electronic modes using the high spatial resolution of STM and AFM. Bare DFT calculations are insufficient to explain the experimental data, which are instead accurately reproduced by many-body corrected GW calculations.
Keywords: Topological Insulators; GW; Atomic Force Microscopy; Scanning Tunneling Microscopy; Spectroscopy