Large Hall and Nernst responses from thermally induced spin chirality in a spin-trimer ferromagnet
Large Hall and Nernst responses from thermally induced spin chirality in a spin-trimer ferromagnet
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DOI：
10.1073/pnas.2023588118
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发表时间：
2021-08-17
影响因子：
11.1
通讯作者：
Tokura, Yoshinori
中科院分区：
文献类型：
--
作者：
Kolincio, Kamil K.;Hirschberger, Max;Tokura, Yoshinori
具有标量自旋手性 (SSC) 的非共面磁性纹理的长程有序可以与传导电子耦合，产生额外的（称为几何或拓扑）霍尔效应。其中一个例子是具有量子化 SSC 的斯格明子晶格态的霍尔效应。获得有限 SSC 的另一种途径是通过铁磁有序转变附近的热波动引起的自旋倾斜。在这里，我们报告说，对于具有二维自旋三聚体阵列的高导铁磁体，热产生的SSC可以产生巨大的几何霍尔电导率，甚至大于基态固有的反常霍尔电导率。我们还证明，热波动引起的 SSC 会导致能斯特效应的强烈响应。对基本单位的波动能斯特和霍尔响应的符号和幅度的比较表明需要动量空间图来模拟这些热感应信号。
The long-range order of noncoplanar magnetic textures with scalar spin chirality (SSC) can couple to conduction electrons to produce an additional (termed geometrical or topological) Hall effect. One such example is the Hall effect in the skyrmion lattice state with quantized SSC. An alternative route to attain a finite SSC is via the spin canting caused by thermal fluctuations in the vicinity of the ferromagnetic ordering transition. Here, we report that for a highly conducting ferromagnet with a two-dimensional array of spin trimers, the thermally generated SSC can give rise to a gigantic geometrical Hall conductivity even larger than the intrinsic anomalous Hall conductivity of the ground state. We also demonstrate that the SSC induced by thermal fluctuations leads to a strong response in the Nernst effect. A comparison of the sign and magnitude of fluctuation-Nernst and Hall responses in fundamental units indicates the need for a momentum- space picture to model these thermally induced signals.