Observation of the anomalous Nernst effect in altermagnetic candidate Mn5Si3
- Antonín Badura
- Warlley H. Campos
- Venkata K. Bharadwaj
- Ismaïla Kounta
- Lisa Michez
- Matthieu Petit
- Javier Rial
- Miina Leiviskä
- Vincent Baltz
- Filip Krizek
- Dominik Kriegner
- Jakub Železný
- Jan Zemen
- Sjoerd Telkamp
- Sebastian Sailler
- Michaela Lammel
- Rodrigo Jaeschke-Ubiergo
- Anna Birk Hellenes
- Rafael González-Hernández
- Jairo Sinova
- Tomas Jungwirth
- Sebastian T. B. Goennenwein
- Libor Šmejkal
- Helena Reichlova
2025-08-02
The anomalous Nernst effect generates a voltage transverse to an applied thermal gradient in some magnetically ordered systems. While the effect was considered excluded in compensated magnetic materials with collinear ordering, in the recently identified symmetry-class of altermagnets, the anomalous Nernst effect is possible despite the compensated collinear spin arrangement. In this work, we show that epitaxial Mn 5 Si 3 thin films grown on Si manifest an anomalous Nernst effect with a finite spontaneous signal at zero magnetic field despite the vanishing spontaneous magnetization. We attribute this to the previously theoretically predicted and experimentally corroborated altermagnetism of epitaxial Mn 5 Si 3 thin films grown on Si. The observed spontaneous anomalous Nernst coefficient reaches the value of 0.26 μV/K with the corresponding spontaneous Nernst conductivity of 0.22 A/(K ⋅ m). To complement our measurements, we perform density-functional theory calculations of the momentum-resolved anomalous Nernst conductivity, highlighting the contributions of altermagnetic pseudonodal surfaces and ladder transitions to the Berry curvature. Our results illustrate the value of unconventional d-wave wave altermagnets composed of abundant and non-toxic light elements for thermo-electrics and spin-caloritronics.