论文标题

在磁非中心对称晶体中观察Weyl Fermions

Observation of Weyl fermions in a magnetic non-centrosymmetric crystal

论文作者

Sanchez, Daniel S., Chang, Guoqing, Belopolski, Ilya, Lu, Hong, Yin, Jia-Xin, Alidoust, Nasser, Xu, Xitong, Cochran, Tyler A., Zhang, Xiao, Bian, Yi, Zhang, Songtian S., Liu, Yi-Yuan, Ma, Jie, Bian, Guang, Lin, Hsin, Xu, Su-Yang, Jia, Shuang, Hasan, M. Zahid

论文摘要

非中心对称材料的特征是没有反转对称性,因为它们表现出铁电性,第二次谐波产生,出现的Weyl Fermions和其他引人入胜的现象。预计,如果时间反转对称性也被损坏,则可能会从磁性和电子阶之间的相互作用中出现其他磁电效应。在这里,我们报告了非中心对称磁铁pralge中的拓扑传导性能。通过光发射光谱法,我们观察到一个参数化的表面置换状态---拓扑弧。使用散装的对应关系,我们得出的结论是,这些弧对应于表面布里鲁因区域的$ \ pm {1} $的预计拓扑电荷,表明在批量中存在磁性韦伊尔准颗粒。我们进一步观察到较大的异常大厅反应,这是由于与磁性Weyl条带结构相关的散装浆果曲率场引起的。我们的结果表明,首次在非中心对称磁铁中具有强大的电子表面状态和异常转运的拓扑阶段,提供了一个新型的材料平台,以研究磁性,带拓扑和传输之间的相互作用。

Characterized by the absence of inversion symmetry, non-centrosymmetric materials are of great interest because they exhibit ferroelectricity, second harmonic generation, emergent Weyl fermions, and other fascinating phenomena. It is expected that if time-reversal symmetry is also broken, additional magneto-electric effects can emerge from the interplay between magnetism and electronic order. Here we report topological conducting properties in the non-centrosymmetric magnet PrAlGe. By photoemission spectroscopy, we observe an arc parametrizing surface-localized states---a topological arc. Using the bulk-boundary correspondence, we conclude that these arcs correspond to projected topological charges of $\pm{1}$ in the surface Brillouin zone, demonstrating the presence of magnetic Weyl quasiparticles in bulk. We further observe a large anomalous Hall response, arising from diverging bulk Berry curvature fields associated with the magnetic Weyl band structure. Our results demonstrate a topological phase with robust electronic surface states and anomalous transport in a non-centrosymmetric magnet for the first time, providing a novel material platform to study the interplay between magnetic order, band topology and transport.

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