Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 21: Poster Monday: Topology and Symmetry-Protected Materials

O 21.1: Poster

Monday, September 5, 2022, 18:00–20:00, P4

Local manifestations of thickness dependent topology and axion edge state in topological magnet MnBi₂Te₄ — •Felix Lüpke^1,2, Anh Pham², Yi-Fan Zhao³, Ling-Jie Zhou³, Wenchang Lu^4,5, Emil Briggs⁴, Jerzy Bernholc^4,5, Marek Kolmer^2,6, Wonhee Ko², Cui-Zu Chang³, Panchapakesan Ganesh², and An-Ping Li² — ¹Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, Germany — ²Center for Nanophase Materials Sciences, Oak Ridge National Lab, USA — ³Physics, The Pennsylvania State University, USA — ⁴Physics, North Carolina State University, USA — ⁵Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37916, USA — ⁶Ames Laboratory, USA

The interplay of non-trivial band topology and magnetism gives rise to a series of exotic quantum phenomena, such as the emergent quantum anomalous Hall (QAH) effect. Many of these phenomena have local manifestations when the global symmetry is broken. Here, we report local signatures of the thickness dependent topology in intrinsic magnetic topological insulator MnBi₂Te₄ (MBT), using scanning tunneling microscopy and spectroscopy on molecular beam epitaxy grown MBT thin films. A thickness-dependent band gap with an oscillatory feature is revealed, which we reproduce with theoretical calculations. At step edges, we observe localized electronic features, in agreement with topological phase transitions across the steps.