Magnetic Weyl semimetal phase in a Kagomé crystal.

Liu, D F; Liang, A J; Liu, E K; Xu, Q N; Li, Y W; Chen, C; Pei, D; Shi, W J et al. · Science · 2019

basic_science · Level V

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Abstract

Weyl semimetals are crystalline solids that host emergent relativistic Weyl fermions and have characteristic surface Fermi-arcs in their electronic structure. Weyl semimetals with broken time reversal symmetry are difficult to identify unambiguously. In this work, using angle-resolved photoemission spectroscopy, we visualized the electronic structure of the ferromagnetic crystal Co<sub>3</sub>Sn<sub>2</sub>S<sub>2</sub> and discovered its characteristic surface Fermi-arcs and linear bulk band dispersions across the Weyl points. These results establish Co<sub>3</sub>Sn<sub>2</sub>S<sub>2</sub> as a magnetic Weyl semimetal that may serve as a platform for realizing phenomena such as chiral magnetic effects, unusually large anomalous Hall effect and quantum anomalous Hall effect.