Magnetoresistance signature of two-dimensional electronic states in Co$_3$Sn$_2$S$_2$

TL;DR

This study investigates the magnetoresistance in Co$_3$Sn$_2$S$_2$, revealing a distinct orbital MR linked to 2D Dirac bands in the kagome lattice, despite dominant 3D bulk contributions.

Contribution

It provides experimental evidence of 2D Dirac band effects in a kagome material through detailed MR analysis, highlighting the orbital MR's dependence on out-of-plane magnetic fields.

Findings

Identification of orbital MR scaling with out-of-plane field

Evidence of 2D Dirac band contribution in a 3D kagome material

Observation of multiple MR components including chiral anomaly

Abstract

Two-dimensional (2D) Dirac bands and flat bands are characteristics of a kagome lattice. However, experimental studies on their electrical transport are few, because three-dimensional (3D) bulk bands of kagome materials, consisting of stacked 2D kagome layers, dominate the transport. We report a magnetoresistance (MR) study of a kagome material, Co$_3$Sn$_2$S$_2$. Based on analysis of the temperature, magnetic field, and field angle dependence of the resistivity, we obtain a complete anatomy of MR. Besides a magnon MR, a chirality-dependent MR, and a chiral-anomaly-induced MR, the most intriguing feature is an orbital MR that scales only with the out-of-plane field, which strongly indicates its 2D nature. We attribute it to the Dirac band of the kagome lattice.