Discovery of Ĉ${}_2$ rotation anomaly in topological crystalline insulator SrPb

Abstract

Topological crystalline insulators (TCIs) are insulating electronic states with nontrivial topology protected by crystalline symmetries. Recently, theory has proposed new classes of TCIs protected by rotation symmetries Ĉ${}_n$, which have surface rotation anomaly evading the fermion doubling theorem, i.e. n instead of 2n Dirac cones on the surface preserving the rotation symmetry. Here, we report the first realization of the Ĉ${}_2$ rotation anomaly in a binary compound SrPb. Our first-principles calculations reveal two massless Dirac fermions protected by the combination of time-reversal symmetry T and Ĉ${}_{2y}$ on the (010) surface. Using angle-resolved photoemission spectroscopy, we identify two Dirac surface states inside the bulk band gap of SrPb, confirming the Ĉ${}_2$ rotation anomaly in the new classes of TCIs. The findings enrich the classification of topological phases, which pave the way for exploring exotic behaviour of the new classes of TCIs.

arXiv comment18 pages, 4 figures

References in corpus (35)

• Topological Insulators
• Topological insulators and superconductors
• Topological Insulators in Three Dimensions
• Maximally localized Wannier functions: Theory and applications
• Classification of topological quantum matter with symmetries
• Type-II Weyl Semimetals
• Topological Crystalline Insulators
• Higher-Order Topological Insulators
• Topological quantum chemistry
• Topological Crystalline Insulators in the SnTe Material Class
• The (High Quality) Topological Materials In The World
• $(d-2)$-dimensional edge states of rotation symmetry protected topological states
• Experimental realization of a topological crystalline insulator in SnTe
• Catalogue of Topological Electronic Materials
• Topological crystalline insulator states in Pb(1-x)Sn(x)Se
• Symmetry-based Indicators of Band Topology in the 230 Space Groups
• Towards ideal topological materials: Comprehensive database searches using symmetry indicators
• Topological Crystalline Insulators and Topological Superconductors: From Concepts to Materials
• A topological crystalline insulator (TCI) phase via topological phase transition and crystalline mirror symmetry
• Lorentz-violating type-II Dirac fermions in transition metal dichalcogenide PtTe${}_2$
• Hourglass Fermions
• Irvsp: to obtain irreducible representations of electronic states in the VASP
• Quantitative mappings between symmetry and topology in solids
• A precise method for visualizing dispersive features in image plots
• Surface States of Topological Crystalline Insulators in IV-VI Semiconductors
• Efficient Topological Materials Discovery Using Symmetry Indicators
• Topological Crystalline Insulators and Dirac Octets in Anti-perovskites
• Experimental Discovery of the First Nonsymmorphic Topological Insulator KHgSb
• Rotation Anomaly and Topological Crystalline Insulators
• Tunability of the k-space Location of the Dirac Cones in the Topological Crystalline Insulator Pb1-xSnxTe
• Topological Materials Discovery By Large-order symmetry indicators
• Purely rotational symmetry-protected topological crystalline insulator $\alpha$-Bi4Br4
• Topological Electronic States in HfRuP Family Superconductors
• Topological Crystalline Insulators with $C_2$ Rotation Anomaly
• Band gap anomaly and topological properties in lead chalcogenides

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