Robust Spin Splitting and Fermiology in the Layered Altermagnet CoNb4Se8
Year: 2026
Type: article
Abstract: ABSTRACT 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.
Source: Advanced Materials
DOI: 10.1002/adma.75367
Authors: Alessandro De Vita, Chiara Bigi, Davide Romanin, Matthew D. Watson, Vincent Polewczyk, Marta Zonno, François Bertran, Pietro M. Forcella, My Bang Petersen, Federico Motti, Giovanni Vinai, Manuel Tuniz, Federico Cilento, Mario Cuoco, Brian M. Andersen, Andreas Kreisel, Luciano Jacopo D'Onofrio, Oliver J. Clark, Mark T. Edmonds, Christopher Candelora, Muxian Xu, Siyu Cheng, Alexander LaFleur, Tommaso Antonelli, Giorgio Sangiovanni, Lorenzo Del Re, Ivana Vobornik, Jun Fujii, Fabio Miletto Granozio, Alessia Sambri, Emiliano Di Gennaro, Jeppe B. Jacobsen, Henrik Jacobsen, Iulia Cojocariu, Marcin Szpytma, Andrea Locatelli, Tevfik Mentes, Won Seop Song, Jun Sung Kim, Matthieu Jamet, Jean‐François Jacquot, Pasquale Orgiani, Ralph Ernstorfer, Ilija Zeljkovic, Younghun Hwang, Matteo Calandra, Jill A. Miwa, Federico Mazzola
Institutions: Fritz Haber Institute of the Max Planck Society, Technische Universität Berlin, Synchrotron SOLEIL, Centre National de la Recherche Scientifique, Université Paris-Saclay, Centre de Nanosciences et de Nanotechnologies, Diamond Light Source, Groupe d’Étude de la Matière Condensée, Aarhus University, AREA Science Park, Istituto Officina dei Materiali, University of Trieste, Elettra-Sincrotrone Trieste S.C.p.A., University of Naples Federico II, University of Copenhagen, University of Salerno, Monash University, Boston College, ETH Zurich, University of Würzburg, Superconducting and other Innovative Materials and Devices Institute, European Spallation Source, AGH University of Krakow, Pohang University of Science and Technology, Institute for Basic Science, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CEA Grenoble, Spintronique et Technologie des Composants, Ulsan College, University of Trento, University of Padua, Institute of Structure of Matter
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $6,070
Funders: U.S. Department of Energy, European Commission, Deutsche Forschungsgemeinschaft, National Research Foundation of Korea, Ministry of Education, Science and Technology, Max-Planck-Gesellschaft, Grand Équipement National De Calcul Intensif, Institute for Basic Science, Ministry of Science and ICT, South Korea, DanScatt, Ministero dell'Università e della Ricerca, Horizon 2020 Framework Programme, European Research Council, Danish Agency for Science and Higher Education, NextGenerationEU
Awards: G1566826928, G174460662, G1752462296, G1942498572, G3076075904, G3569481192, G4494698904, G4703204821, G4846862643, G5099004511, G5737734281, G6153623005, G642729774, Selectively activated INFOrmation technology by hybrid Organic Interfaces, G6657335195, G6756800653, G6855543015, G7476165923, G7604540477, G7605500907, G7981290831
OpenAlex ID: W4415957658