Badura Antonín, Campos Warlley H, Bharadwaj Venkata K, Kounta Ismaïla, Michez Lisa, Petit Matthieu, Rial Javier, Leiviskä Miina, Baltz Vincent, Krizek Filip, Kriegner Dominik, Železný Jakub, Zemen Jan, Telkamp Sjoerd, Sailler Sebastian, Lammel Michaela, Jaeschke-Ubiergo Rodrigo, Hellenes Anna Birk, González-Hernández Rafael, Sinova Jairo, Jungwirth Tomáš, Goennenwein Sebastian T B, Šmejkal Libor, Reichlova Helena
Institute of Physics, Czech Academy of Sciences, Prague, Czechia.
Faculty of Mathematics and Physics, Charles University, Prague, Czechia.
Nat Commun. 2025 Aug 2;16(1):7111. doi: 10.1038/s41467-025-62331-7.
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 MnSi 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 MnSi 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.
反常能斯特效应在一些磁有序系统中会产生一个与外加热梯度垂直的电压。虽然在具有共线有序的补偿磁性材料中该效应被认为不存在，但在最近发现的交替磁体对称类中，尽管自旋排列是补偿共线的，反常能斯特效应仍是可能的。在这项工作中，我们表明生长在硅上的外延MnSi薄膜表现出反常能斯特效应，在零磁场下具有有限的自发信号，尽管自发磁化强度消失。我们将此归因于先前理论预测并经实验证实的生长在硅上的外延MnSi薄膜的交替磁性。观测到的自发反常能斯特系数达到0.26 μV/K的值，相应的自发能斯特电导率为0.22 A/(K ⋅ m)。为补充我们的测量，我们对动量分辨的反常能斯特电导率进行了密度泛函理论计算，突出了交替磁伪节点表面和阶梯跃迁对贝里曲率的贡献。我们的结果说明了由丰富且无毒的轻元素组成的非常规d波交替磁体在热电学和自旋热电子学方面的价值。
