Robust Spin Splitting and Fermiology in the Layered Altermagnet CoNb4Se8

@article{vita2026robust,
  title = {{Robust Spin Splitting and Fermiology in the Layered Altermagnet CoNb4Se8}},
  author = {Alessandro De Vita and Chiara Bigi and Davide Romanin and Matthew D. Watson and Vincent Polewczyk and Marta Zonno and F. Bertran and Pietro Maria Forcella and My Bang Petersen and Federico Motti and Giovanni Vinai and Manuel Tuniz and Federico Cilento and Mario Cuoco and Brian M. Andersen and Andreas Kreisel and Luciano Jacopo D’Onofrio and Oliver J. Clark and Mark T. Edmonds and Christopher Candelora and Muxian Xu and Siyu Cheng and Alexander LaFleur and Tommaso Antonelli and Giorgio Sangiovanni and Lorenzo Del Re and I. Vobornik and Jun Fujii and F. Miletto Granozio and A. Sambri and Emiliano Di Gennaro and H. Jacobsen and H. Jacobsen and Iulia Cojocariu and Marcin Szpytma and Andrea Locatelli and Tevfik Onur Menteş and Won Seop Song and Jun Sung Kim and Matthieu Jamet and Jean‐François Jacquot and P. Orgiani and Ralph Ernstorfer and Ilija Zeljkovic and Y. T. Hwang and Jill A. Miwa and Jill A. Miwa and Federico Mazzola},
  journal = {Advanced Materials},
  year = {2026},
  month = oct,
  doi = {10.1002/adma.75367},
  url = {https://doi.org/10.1002/adma.75367},
  note = {CC BY},
}

TY  - JOUR
TI  - Robust Spin Splitting and Fermiology in the Layered Altermagnet CoNb4Se8
AU  - Alessandro De Vita
AU  - Chiara Bigi
AU  - Davide Romanin
AU  - Matthew D. Watson
AU  - Vincent Polewczyk
AU  - Marta Zonno
AU  - F. Bertran
AU  - Pietro Maria Forcella
AU  - My Bang Petersen
AU  - Federico Motti
AU  - Giovanni Vinai
AU  - Manuel Tuniz
AU  - Federico Cilento
AU  - Mario Cuoco
AU  - Brian M. Andersen
AU  - Andreas Kreisel
AU  - Luciano Jacopo D’Onofrio
AU  - Oliver J. Clark
AU  - Mark T. Edmonds
AU  - Christopher Candelora
AU  - Muxian Xu
AU  - Siyu Cheng
AU  - Alexander LaFleur
AU  - Tommaso Antonelli
AU  - Giorgio Sangiovanni
AU  - Lorenzo Del Re
AU  - I. Vobornik
AU  - Jun Fujii
AU  - F. Miletto Granozio
AU  - A. Sambri
AU  - Emiliano Di Gennaro
AU  - H. Jacobsen
AU  - H. Jacobsen
AU  - Iulia Cojocariu
AU  - Marcin Szpytma
AU  - Andrea Locatelli
AU  - Tevfik Onur Menteş
AU  - Won Seop Song
AU  - Jun Sung Kim
AU  - Matthieu Jamet
AU  - Jean‐François Jacquot
AU  - P. Orgiani
AU  - Ralph Ernstorfer
AU  - Ilija Zeljkovic
AU  - Y. T. Hwang
AU  - Jill A. Miwa
AU  - Jill A. Miwa
AU  - Federico Mazzola
PY  - 2026
DA  - 2026/10/18
JO  - Advanced Materials
DO  - 10.1002/adma.75367
UR  - https://doi.org/10.1002/adma.75367
AB  - Altermagnetism defies conventional classifications of collinear magnetic phases, combining compensated magnetization with momentum‐dependent, nonrelativistic spin splitting. While altermagnetic band splitting has been established in three‐dimensional compounds such as MnTe and CrSb, layered altermagnets remain far less explored spectroscopically. Here, combining termination‐resolved micro‐ARPES, fine photon‐energy mapping, spin‐ARPES, and density functional theory, we map the three‐dimensional fermiology of the layered g ‐wave altermagnet , obtained by ordered Co intercalation of 2H‐. We resolve the spin–split branches of the altermagnetic pairs directly in the raw photoemission spectra and, with spin‐ARPES at these experimentally identified momenta, show the reversal of the spin polarization at opposite momenta and between two regions of the sample, consistent with opposite time‐reversal domains, and its absence along the symmetry‐protected nodal –K direction. We further report a weak low‐temperature anomaly near T 0 ≈ 50–60 K, detected by magnetometry, temperature‐dependent micro‐ARPES, and ultrafast reflectivity, whose microscopic origin remains open. These results provide a momentum‐resolved benchmark of the electronic structure of a layered altermagnet.
SN  - 0935-9648
SN  - 1521-4095
ER  -