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Discovery of a weak topological insulating state and van Hove singularity in triclinic RhBi2.

Published version
Peer-reviewed

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Type

Article

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Authors

Lee, Kyungchan 
Lange, Gunnar F 
Kuthanazhi, Brinda 

Abstract

Time reversal symmetric (TRS) invariant topological insulators (TIs) fullfil a paradigmatic role in the field of topological materials, standing at the origin of its development. Apart from TRS protected strong TIs, it was realized early on that more confounding weak topological insulators (WTI) exist. WTIs depend on translational symmetry and exhibit topological surface states only in certain directions making it significantly more difficult to match the experimental success of strong TIs. We here report on the discovery of a WTI state in RhBi2 that belongs to the optimal space group P[Formula: see text], which is the only space group where symmetry indicated eigenvalues enumerate all possible invariants due to absence of additional constraining crystalline symmetries. Our ARPES, DFT calculations, and effective model reveal topological surface states with saddle points that are located in the vicinity of a Dirac point resulting in a van Hove singularity (VHS) along the (100) direction close to the Fermi energy (EF). Due to the combination of exotic features, this material offers great potential as a material platform for novel quantum effects.

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Keywords

cond-mat.str-el, cond-mat.str-el, cond-mat.other

Journal Title

Nat Commun

Conference Name

Journal ISSN

2041-1723
2041-1723

Volume Title

12

Publisher

Springer Science and Business Media LLC
Sponsorship
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (842901)