Signatures of Kramers-Weyl fermions in the charge density wave material (TaSe4)2I
The quasi-one-dimensional charge density wave (CDW) material (TaSe4)2I has been recently predicted to host Kramers-Weyl (KW) fermions which should exist in the vicinity of high symmetry points in the Brillouin zone in chiral materials with strong spin-orbit coupling. However, direct spectroscopic evidence of KW fermions is limited. Here we use helicity-dependent laser-based angle-resolved photoemission spectroscopy (ARPES) in conjunction with tight-binding and first-principles calculations to identify KW fermions in (TaSe4)2I. We find that topological and symmetry considerations place distinct constraints on the (pseudo-) spin texture and the observed spectra around a KW node. Our findings highlight the unique topological nature of (TaSe4)2I and provide a pathway for identifying KW fermions in other chiral materials. It has been predicted that the quasi-one-dimensional charge density wave material (TaSe4)2I hosts Kramers-Weyl fermions, but direct spectroscopic evidence of this is limited. Here, ARPES and theoretical calculations reveal signatures that may indicate the presence of Kramers-Weyl fermions.
Authors
- T.‐C. Chiang (ORCID: https://orcid.org/0000-0001-7118-8299)
- Nina Bielinski (ORCID: https://orcid.org/0009-0002-7970-3659)
- Fahad Mahmood
- Xuefei Guo (ORCID: https://orcid.org/0000-0003-1088-6039)
- Daniel P. Shoemaker (ORCID: https://orcid.org/0000-0003-3650-7551)
- Robert C. McKay (ORCID: https://orcid.org/0000-0002-7684-6059)
- Meng-Kai Lin (ORCID: https://orcid.org/0000-0002-8713-3230)
- Junehu Park (ORCID: https://orcid.org/0000-0002-3432-3743)
- Sung‐Kwan Mo (ORCID: https://orcid.org/0000-0003-0711-8514)
- Barry Bradlyn (ORCID: https://orcid.org/0000-0001-6327-1076)
- Peter Abbamonte (ORCID: https://orcid.org/0000-0003-1109-1510)
- Joseph A. Hlevyack (ORCID: https://orcid.org/0000-0001-7057-9335)
- André Schleife (ORCID: https://orcid.org/0000-0003-0496-8214)
- Soyeun Kim (ORCID: https://orcid.org/0000-0002-4522-6834)
- Chengxi Zhao (ORCID: https://orcid.org/0000-0001-7671-5262)
Institutions
- Lawrence Berkeley National Laboratory (US)
- University of Illinois Urbana-Champaign (US)
- Urbana University (US)
- Daegu Gyeongbuk Institute of Science and Technology (KR)
- National Central University (TW)
- National Center for Supercomputing Applications (US)
Publication Details
- Journal
- Communications Materials
- Published
- 2025-10-20
- DOI
- https://doi.org/10.1038/s43246-025-00952-7
- Citations
- 1
- Primary Topic
- Organic and Molecular Conductors Research
- Type
- article
- Field-Weighted Citation Impact
- 0.43
Funders
- National Science Foundation
- U.S. Department of Energy
- Gordon and Betty Moore Foundation
- National Centre for Supercomputing Applications
- Daegu Gyeongbuk Institute of Science and Technology
- Ministry of Science and ICT, South Korea
- University of Illinois at Urbana-Champaign
- Office of Science
- Materials Research Science and Engineering Center, Harvard University
- Division of Materials Research
- Basic Energy Sciences