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MA: Fachverband Magnetismus

MA 15: Topological Insulators and Weyl Semimetals (joint session MA/TT)

MA 15.7: Talk

Tuesday, March 19, 2024, 11:00–11:15, H 2013

The MT Protected Topological States and Local Symmetry in 2D Antiferromagnetic SrMn2Bi2 — •Hao Wang¹, Chengwang Niu², Libor Smejkal^3,4, and Yuriy Mokrousov^1,3 — ¹Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany — ²School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China — ³Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany — ⁴Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnicka 10, Praha 6, Czech Republic

Antiferromagnetic topological insulators (AFMTIs) represent a novel class of topological states for spintronics. Understanding symmetry protection and exploring AFMTIs with desirable properties are crucial. In this study, through first-principles calculations and symmetry analysis, we investigate the topological properties of monolayer SrMn2Bi2, demonstrating sensitivity to magnetic configurations. In the out-of-plane AFM ground state, we observe a gapless helical edge state protected by the mirror plane combined with time-reversal symmetry. In the FM state, this system resides in a quantum anomalous Hall phase, and topology trivial for in-plane magnetization. We show that the topological properties can be efficiently manipulated by strain. Additionally, constructing proper Wannier functions obeying symmetry constraints is crucial to avoid spurious states in surface spectra. Our work provides an ideal candidate for AFMTIs and guides the symmetry analysis of magnetic topological materials using Wannier functions.

Keywords: topological insulators; antiferromagnetism; first-principles calculation