Observation of a spontaneous anomalous Hall response in the Mn 5 Si 3 d-wave altermagnet candidate

• Published in: Nature communications Vol. 15; no. 1; p. 4961
• Main Authors: Reichlova, Helena, Lopes Seeger, Rafael, González-Hernández, Rafael, Kounta, Ismaila, Schlitz, Richard, Kriegner, Dominik, Ritzinger, Philipp, Lammel, Michaela, Leiviskä, Miina, Birk Hellenes, Anna, Olejník, Kamil, Petřiček, Vaclav, Doležal, Petr, Horak, Lukas, Schmoranzerova, Eva, Badura, Antonín, Bertaina, Sylvain, Thomas, Andy, Baltz, Vincent, Michez, Lisa, Sinova, Jairo, Goennenwein, Sebastian T B, Jungwirth, Tomáš, Šmejkal, Libor
• Format: Journal Article
• Language: English
• Published: England 11.06.2024
• ISSN: 2041-1723

Phases with spontaneous time-reversal ( ) symmetry breaking are sought after for their anomalous physical properties, low-dissipation electronic and spin responses, and information-technology applications. Recently predicted altermagnetic phase features an unconventional and attractive combination of a strong -symmetry breaking in the electronic structure and a zero or only weak-relativistic magnetization. In this work, we experimentally observe the anomalous Hall effect, a prominent representative of the -symmetry breaking responses, in the absence of an external magnetic field in epitaxial thin-film Mn Si with a vanishingly small net magnetic moment. By symmetry analysis and first-principles calculations we demonstrate that the unconventional d-wave altermagnetic phase is consistent with the experimental structural and magnetic characterization of the Mn Si epilayers, and that the theoretical anomalous Hall conductivity generated by the phase is sizable, in agreement with experiment. An analogy with unconventional d-wave superconductivity suggests that our identification of a candidate of unconventional d-wave altermagnetism points towards a new chapter of research and applications of magnetic phases.