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

TL;DR

This study investigates how magnetic field orientation affects the Fermi surface and electronic structure in ferromagnetic Weyl semimetal Co3Sn2S2, revealing an anisotropic interplay between magnetism and electronic topology.

Contribution

It provides experimental evidence of field-dependent evolution of Fermi surfaces and Weyl points driven by magnetic moment orientation in a ferromagnetic Weyl semimetal.

Findings

In-plane magnetic field causes continuous Fermi surface evolution.

Field perpendicular to kagome planes has minimal effect.

Electronic structure depends on ferromagnetic moment orientation.

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.