Dresden 2026 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 28: Topology and symmetry protected materials & Topological insulators (joint session O/HL/TT)
HL 28.10: Vortrag
Mittwoch, 11. März 2026, 17:15–17:30, HSZ/0401
Simultaneous Characterization of Dispersion and Orbital Character of the Topological Surface State on the Topological Insulator Bi2Te3 — •Christoph Stephen Setescak, Adrian Weindl, and Franz Josef Giessibl — Universität Regensburg, D-93053 Regensburg
Scanning probe microscopy (STM and AFM) allows one to locally probe properties of topological insulators (TIs). On the compound Bi2Te3, atomic-scale electronic standing waves can be observed at crystalline step edges, which are associated with the hexagonal warping of the Dirac cone. These real-space oscillations provide a direct means to study the dispersion relation of the topological boundary mode. The interpretation relies on comparing the experimental data to calculations including not only the properties of the TI but also of the tip. In this framework, the tunneling current and differential conductance is modelled using Chen’s derivative rule. Bending of the CO molecule at the tip apex due to lateral tip-sample forces is also included in the model. The relevant Bloch functions of the sample are obtained from Wannier-interpolated tight-binding Hamiltonians using maximally localized Wannier functions derived from first-principles DFT + GW computations. In combination with the high spatial resolution obtained with CO-terminated tips, not only the dispersion, but also the orbital character of the band structure can be probed.
Keywords: Topological Insulators; Scanning Tunneling Microscopy; Atomic Force Microscopy; GW-DFT; Tight-binding method