论文标题

co $ _2 $ mnga的异常横向响应和室温的通用性$α^a_ {ij}/σ^a__ {ij} $ ratio topogical Magnets

Anomalous transverse response of Co$_2$MnGa and universality of the room-temperature $α^A_{ij}/σ^A_{ij}$ ratio across topological magnets

论文作者

Xu, Liangcai, Li, Xiaokang, Ding, Linchao, Chen, Taishi, Sakai, Akito, Fauqué, Benoît, Nakatsuji, Satoru, Zhu, Zengwei, Behnia, Kamran

论文摘要

由于Bloch波的非平凡拓扑,固体的异常(电,热和热电)传输系数可以获取异常组件。我们提出了一项关于Heusler Weyl Ferromagnet Co $ _2 $ MNGA中异常大厅(AHE),Nernst(ANE)和热厅效应(ATHE)的研究。在整个温度窗口上,发现无针对电响应的无异常的Wiedemann-Franz定律有效。这表明AHE具有固有的起源,并且在费米水平的附近,浆果光谱是光滑的。从ANE数据中,我们提取$α^a_ {ij} $的幅度和温度依赖性,并在审查$α^a_ {ij}/σ^a_ {ij} $比率下进行审查,该$ _b $/e接近室温。 We show that in various topological magnets the room-temperature magnitude of this ratio is a sizeable fraction of k$_B$/e and argue that the two anomalous transverse coefficients depend on universal constants, the Berry curvature averaged over a window set by either the Fermi wavelength (for Hall) or the de Broglie thermal length (for Nernst).由于后两者的比率接近室温下的统一,因此这种通用缩放在异常横向系数的内在图片中发现了自然的解释。

The off-diagonal (electric, thermal and thermoelectric) transport coefficients of a solid can acquire an anomalous component due to the non-trivial topology of the Bloch waves. We present a study of the anomalous Hall (AHE), Nernst (ANE) and thermal Hall effects (ATHE) in the Heusler Weyl ferromagnet Co$_2$MnGa. The Anomalous Wiedemann-Franz law, linking electric and thermal responses, was found to be valid over the whole temperature window. This indicates that the AHE has an intrinsic origin and the Berry spectrum is smooth in the immediate vicinity of the Fermi level. From the ANE data, we extract the magnitude and temperature dependence of $α^A_{ij}$ and put under scrutiny the $α^A_{ij}/σ^A_{ij}$ ratio, which approaches k$_B$/e at room temperature. We show that in various topological magnets the room-temperature magnitude of this ratio is a sizeable fraction of k$_B$/e and argue that the two anomalous transverse coefficients depend on universal constants, the Berry curvature averaged over a window set by either the Fermi wavelength (for Hall) or the de Broglie thermal length (for Nernst). Since the ratio of the latter two is close to unity at room temperature, such a universal scaling finds a natural explanation in the intrinsic picture of anomalous transverse coefficients.

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