Asaba T, Ivanov V, Thomas S M, Savrasov S Y, Thompson J D, Bauer E D, Ronning F
Materials Physics and Applications Division, Los Alamos National Laboratory, NM, 87545 USA.
Department of Physics, University of California, Davis, CA 95616, USA.
Sci Adv. 2021 Mar 26;7(13). doi: 10.1126/sciadv.abf1467. Print 2021 Mar.
The transverse voltage generated by a temperature gradient in a perpendicularly applied magnetic field, termed the Nernst effect, has promise for thermoelectric applications and for probing electronic structure. In magnetic materials, an anomalous Nernst effect (ANE) is possible in a zero magnetic field. We report a colossal ANE in the ferromagnetic metal UCoRuAl, reaching 23 microvolts per kelvin. Uranium's 5 electrons provide strong electronic correlations that lead to narrow bands, a known route to producing a large thermoelectric response. In addition, uranium's strong spin-orbit coupling produces an intrinsic transverse response in this material due to the Berry curvature associated with the relativistic electronic structure. Theoretical calculations show that in UCoRuAl at least 148 Weyl nodes, and two nodal lines, exist within 60 millielectron volt of the Fermi level. This work demonstrates that magnetic actinide materials can host strong Nernst and Hall responses due to their combined correlated and topological nature.
在垂直施加的磁场中，由温度梯度产生的横向电压，即能斯特效应，在热电应用和探测电子结构方面具有潜力。在磁性材料中，零磁场下可能会出现反常能斯特效应（ANE）。我们报道了铁磁金属UCoRuAl中存在巨大的反常能斯特效应，达到每开尔文23微伏。铀的5个电子提供了强电子关联，导致能带变窄，这是产生大热电响应的已知途径。此外，由于与相对论电子结构相关的贝里曲率，铀的强自旋轨道耦合在这种材料中产生了固有横向响应。理论计算表明，在UCoRuAl中，费米能级60毫电子伏特范围内至少存在148个外尔点和两条节线。这项工作表明，磁性锕系材料由于其关联和拓扑性质的结合，能够呈现出强能斯特和霍尔响应。
