Dresden 2026 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 55: Topology and symmetry protected materials & Topological insulators (joint session O/HL/TT)
TT 55.11: Vortrag
Mittwoch, 11. März 2026, 17:30–17:45, HSZ/0401
Defect-induced displacement of topological surface state in magnetic topological insulator MnBi2Te4 — •Felix Lüpke1,2, Marek Kolmer3,4, Hengxin Tan5, Adam Kaminski3,4, and Binghai Yan5,6 — 1Peter Grünberg Institute (PGI-3) and JARA-FIT, Forschungszentrum Jülich, 52425 Jülich, Germany — 2Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany — 3Ames National Laboratory, Ames, Iowa 50011, USA — 4Iowa State University, Ames, Iowa 50011, USA — 5Weizmann Institute of Science, Rehovot 7610001, Israel — 6The Pennsylvania State University, University Park, Pennsylvania 16802, USA
The gapped topological surface states of MnBi2Te4 (MBT) are an attractive platform for the realization of quantum anomalous Hall and Axion insulator states. However, experimentally observed surface state gaps fail to meet theoretical predictions, with the exact mechanism behind the gap suppression still being debated. We report on the effect of intrinsic anti-site defects on the MBT surface states, which we study using scanning tunneling microscopy (STM), angle-resolved photoemission (ARPES), and density functional theory (DFT). Our results show that high defect concentrations lead to a displacement of the surface states into the interior of the MBT crystal, consistent with theoretical predicitons [PRL 130, 126702 (2023)].
Keywords: Magnetic topological insulators; Lattice defects; Scanning tunneling microscopy; Angle-resolved photoemission spectroscopy; Density functional theory