Giant anomalous Hall angle in a half-metallic magnetic Weyl semimetal
Giant anomalous Hall angle in a half-metallic magnetic Weyl semimetal
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2017
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通讯作者：
Enke Liu;Yan Sun;Lukas Müchler;Aili Sun;L. Jiao;Johannes Kroder;V. Süss;H. Borrmann;Wenhong Wang;W. Schnelle;S. Wirth;B. SebastianT.;Goennenwein;C. Felser
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作者：
Enke Liu;Yan Sun;Lukas Müchler;Aili Sun;L. Jiao;Johannes Kroder;V. Süss;H. Borrmann;Wenhong Wang;W. Schnelle;S. Wirth;B. SebastianT.;Goennenwein;C. Felser
具有时间反演对称性破缺的磁性外尔半金属（WSM）表现出外尔节点，其充当Berry曲率的单极子，因此有望产生大的本征反常霍尔效应（AHE）。然而，在大多数磁性WSM中，Weyl节点位于远离费米能量的位置，使得在实验中难以观察到Weyl节点主导的本征AHE。在这里，我们报告了一种新的半金属磁性WSM在Kagomé晶格Shandite化合物Co 3Sn 2S 2。外尔节点，由有间隙的节点环连接，位于费米能量上方60 meV的关键位置。由于外尔带产生的显著增强的Berry曲率和低电荷电导率，反常霍尔电导率（AHC）和反常霍尔角（AHA）实验上分别达到1130 Ω −1 cm −1和20%，这使得材料同时拥有大AHC和巨AHA。将WSM解释为耦合量子AHE层，目前的结果表明，这种准二维WSM薄膜为体绝缘量子AHE提供了一个有希望的候选者。因此，Co 3Sn 2S 2作为一种易于生长的磁性WSM代表了研究Weyl物理的理想平台。我们的研究结果进一步表明，半金属外尔半金属-结合拓扑外尔相的一个自旋通道与带隙的其他-作为一个新的范例，材料与一个大的贝里在原产地AHE。
Magnetic Weyl semimetals (WSMs) with time reversal symmetry breaking exhibit Weyl nodes that act as monopoles of Berry curvature and are thus expected to generate a large intrinsic anomalous Hall effect (AHE). However, in most magnetic WSMs, the Weyl nodes are located far from the Fermi energy, making it difficult to observe the Weyl-node dominated intrinsic AHE in experiments. Here we report a novel half-metallic magnetic WSM in the Kagomé-lattice Shandite compound Co3Sn2S2. The Weyl nodes, linked by gapped nodal rings, are crucially located just 60 meV above the Fermi energy. Owing to both the significantly enhanced Berry curvature arising from the Weyl bands and the low charge conductivity, the anomalous Hall conductivity (AHC) and anomalous Hall angle (AHA) experimentally reach up to 1130 Ω −1 cm −1 and 20% respectively, which allows the material to simultaneously host a large AHC and giant AHA. Interpreting WSMs as coupled quantum AHE layers, the present results suggest that thin films of this quasi-two-dimensional WSM present a promising candidate for the bulk-insulating quantum AHE. Co3Sn2S2 as an easy-to-grow magnetic WSM thus represents an ideal platform to study Weyl physics. Our findings further suggest half-metallic Weyl semimetals – combining a topological Weyl phase for one spin channel with a band gap for the other – as a new paradigm for materials with a large Berry-in-origin AHE.