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arXiv 2109.09382cond-mat.mtrl-sciphysics.chem-ph
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反铁磁体YbMnBi2中的巨反常能斯特信号

Giant anomalous Nernst signal in the antiferromagnet YbMnBi2

Yu Pan, Congcong Le, Bin He, Sarah J. Watzman, Mengyu Yao, Johannes Gooth, Joseph P. Heremans, Yan Sun, Claudia Felser

摘要:

寻找高反常能斯特效应(ANE)对于热电能量转换应用是至关重要的,因为相关的独特横向几何形状有利于模块制造。具有大Berry曲率的拓扑铁磁体显示出高ANE;然而,它们面临着诸如强磁扰动和由于高磁化而导致的低迁移率的缺点。在这里,我们证明了YbMnBi 2,一个倾斜的反铁磁体,具有大的ANE电导率~10 Am-1 K-1,超过了目前在铁磁体中观察到的常见的高值(即3-5 Am-1 K-1)。Mn的倾斜自旋结构保证了非零的Berry曲率,但只产生比一般铁磁体低三个数量级的弱磁化。具有大自旋轨道耦合的重Bi使得高ANE和低热导率成为可能,而其高度分散的px/y轨道确保低电阻率。高的反常横向热电性能和极小的磁化强度使YbMnBi 2成为横向热电的优秀候选者。

英文摘要:

Searching for a high anomalous Nernst effect (ANE) is crucial for thermoelectric energy conversion applications because the associated unique transverse geometry facilitates module fabrication. Topological ferromagnets with large Berry curvatures show high ANEs; however, they face drawbacks such as strong magnetic disturbances and low mobility due to high magnetization. Herein, we demonstrate that YbMnBi2, a canted antiferromagnet, has a large ANE conductivity of ~10 Am-1K-1 that surpasses the common high values (i.e. 3-5 Am-1K-1) observed so far in ferromagnets. The canted spin structure of Mn guarantees a nonzero Berry curvature but generates only a weak magnetization three orders of magnitude lower than that of general ferromagnets. The heavy Bi with a large spin-orbit coupling enables a high ANE and low thermal conductivity, whereas its highly dispersive px/y orbitals ensure low resistivity. The high anomalous transverse thermoelectric performance and extremely small magnetization makes YbMnBi2 an excellent candidate for transverse thermoelectrics.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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