Large anomalous Hall effect and negative magnetoresistance in half-topological semimetals
Large anomalous Hall effect and negative magnetoresistance in half-topological semimetals
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DOI：
10.1038/s42005-023-01469-6
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发表时间：
2023-11
影响因子：
5.5
通讯作者：
Yanglin Zhu;Cheng-Yi Huang;Yu Wang;David Graf;Hsin Lin;Seng Huat Lee;John Singleton;L. Min;J. C. Palmstrom;Arun Bansil;Bahadur Singh;Zhiqiang Mao
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作者：
Yanglin Zhu;Cheng-Yi Huang;Yu Wang;David Graf;Hsin Lin;Seng Huat Lee;John Singleton;L. Min;J. C. Palmstrom;Arun Bansil;Bahadur Singh;Zhiqiang Mao
磁性拓扑半金属中大本征反常霍尔效应（AHE）的拟议机制包括韦尔节点的发散贝里曲率、反交叉节点环或非平凡带点。在这里，我们通过对反铁磁（AFM）半赫斯勒化合物 TbPdBi 的系统研究证明，拓扑临界点附近的半拓扑半金属（HTS）态可以为大 AHE 提供替代机制。我们不仅在其场驱动铁磁 (FM) 相中观察到 tanθH≈ 2 的大型 AHE，而且还在其倾斜的 AFM 相中发现了明显的霍尔电阻率峰值。此外，我们观察到了大约 98% 的大负磁阻。我们深入的理论模型表明，这些奇异的输运特性源自 HTS 状态，该状态在平凡的自旋向上和非平凡的自旋向下带之间表现出贝里曲率抵消。我们的研究为改进自旋电子学和其他应用的材料设计提供了替代策略。
Proposed mechanisms for large intrinsic anomalous Hall effect (AHE) in magnetic topological semimetals include diverging Berry curvatures of Weyl nodes, anticrossing nodal rings or points of non-trivial bands. Here we demonstrate that a half-topological semimetal (HTS) state near a topological critical point can provide an alternative mechanism for a large AHE via systematic studies on an antiferromagnetic (AFM) half-Heusler compound TbPdBi. We not only observe a large AHE with tanΘH≈ 2 in its field-driven ferromagnetic (FM) phase, but also find a distinct Hall resistivity peak in its canted AFM phase. Moreover, we observe a large negative magnetoresistance with a value of ~98%. Our in-depth theoretical modelling indicates that these exotic transport properties originate from the HTS state which exhibits Berry curvature cancellation between the trivial spin-up and nontrivial spin-down bands. Our study offers alternative strategies for improved materials design for spintronics and other applications.