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DOE OSTI · 2281407

Spin-resolved topology and partial axion angles in three-dimensional insulators

Lin, Kuan-Sen (ORCID:0009000555178097)·Palumbo, Giandomenico·Guo, Zhaopeng·Hwang, Yoonseok·Blackburn, Jeremy·Shoemaker, Daniel P. (ORCID:0000000336507551)·Mahmood, Fahad (ORCID:0000000296413453)·Wang, Zhijun (ORCID:0000000321698068)·Fiete, Gregory A. (ORCID:0000000194770804)·Wieder, Benjamin J. (ORCID:0000000325406202)·Bradlyn, Barry (ORCID:0000000163271076)
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Abstract

Abstract Symmetry-protected topological crystalline insulators (TCIs) have primarily been characterized by their gapless boundary states. However, in time-reversal- ( $${{{{{{{\mathcal{T}}}}}}}}$$ T -) invariant (helical) 3D TCIs—termed higher-order TCIs (HOTIs)—the boundary signatures can manifest as a sample-dependent network of 1D hinge states. We here introduce nested spin-resolved Wilson loops and layer constructions as tools to characterize the intrinsic bulk topological properties of spinful 3D insulators. We discover that helical HOTIs realize one of three spin-resolved phases with distinct responses that are quantitatively robust to large deformations of the bulk spin-orbital texture: 3D quantum spin Hall insulators (QSHIs), “spin-Weyl” semimetals, and $${{{{{{{\mathcal{T}}}}}}}}$$ T -doubled axion insulator (T-DAXI) states with nontrivial partial axion angles indicative of a 3D spin-magnetoelectric bulk response and half-quantized 2D TI surface states originating from a partial parity anomaly. Using ab-initio calculations, we demonstrate that β -MoTe 2 realizes a spin-Weyl state and that α -BiBr hosts both 3D QSHI and T-DAXI regimes.

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75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITYElectronic properties and materialsSpin-orbit couplingSpintronicsTopological insulatorsTopology

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Lin, Kuan-Sen (ORCID:0009000555178097), Palumbo, Giandomenico, Guo, Zhaopeng, Hwang, Yoonseok, Blackburn, Jeremy, Shoemaker, Daniel P. (ORCID:0000000336507551), Mahmood, Fahad (ORCID:0000000296413453), Wang, Zhijun (ORCID:0000000321698068), Fiete, Gregory A. (ORCID:0000000194770804), Wieder, Benjamin J. (ORCID:0000000325406202), Bradlyn, Barry (ORCID:0000000163271076). 2024-01-16. Spin-resolved topology and partial axion angles in three-dimensional insulators. https://doi.org/10.1038/s41467-024-44762-w

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