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Mobius Insulator and Higher-Order Topology in MnBi2nTe3n+1

TitleMobius Insulator and Higher-Order Topology in MnBi2nTe3n+1
Publication TypeJournal Article
Year of Publication2020
AuthorsR-X. Zhang, F. Wu, and S. Das Sarma
JournalPhys. Rev. Lett.
Date PublishedAPR 3
Type of ArticleArticle

We propose MnBi2nTe3n+1 as a magnetically tunable platform for realizing various symmetry-protected higher-order topology. Its canted antiferromagnetic phase can host exotic topological surface states with a Mobius twist that are protected by nonsymmorphic symmetry. Moreover, opposite surfaces hosting Mobius fermions are connected by one-dimensional chiral hinge modes, which offers the first material candidate of a higher-order topological Mobius insulator. We uncover a general mechanism to feasibly induce this exotic physics by applying a small in-plane magnetic field to the antiferromagnetic topological insulating phase of MnBi2nTe3n+1, as well as other proposed axion insulators. For other magnetic configurations, two classes of inversion-protected higher-order topological phases are ubiquitous in this system, which both manifest gapped surfaces and gapless chiral hinge modes. We systematically discuss their classification, microscopic mechanisms, and experimental signatures. Remarkably, the magnetic-field-induced transition between distinct chiral hinge mode configurations provides an effective ``topological magnetic switch{''}.