Field-dependent Shubnikov-de Haas oscillations in ferromagnetic Weyl semimetal Co3Sn2S2

Abstract: We report a study of Shubnikov-de Haas oscillations in high quality single crystals of ferromagnetic Weyl semimetal Co$_3$Sn$_2$S$_2$. The Fermi surfaces resolved in our experiments are three-dimensional and reflect an underlying trigonal crystallographic symmetry. Combined with density functional theoretical calculations, we identify that the majority of the Fermi surfaces in the system -- of both electron and hole nature -- arise from the strong energy dispersion of the (spin-orbit gapped) mirror-protected nodal rings. We observe that an in-plane magnetic field induces a continuous evolution of Fermi surfaces, in contrast to field perpendicular to the kagome lattice planes which has little effect. Viewed alongside the easy-axis anisotropy of the system, our observation reveals an evolution of the electronic structure of Co$_3$Sn$_2$S$_2$ -- including the Weyl points -- with the ferromagnetic moment orientation. Through the case study of Co$_3$Sn$_2$S$_2$, our results provide concrete experimental evidence of an anisotropic interplay via spin-orbit coupling between the magnetic degrees of freedom and electronic band singularities, which has long been expected in semimetallic and metallic magnetic topological systems.