Two-dimensionality of metallic surface conduction in Co3Sn2S2 thin films

TL;DR

This study demonstrates that Co3Sn2S2 thin films exhibit a 2D surface conduction path associated with Weyl semimetal properties, with a surface conduction region approximately 20 nm thick, relevant for quantum and spintronic applications.

Contribution

It provides the first systematic measurement of the dimensionality of surface conduction in Co3Sn2S2 thin films, revealing a 20 nm thick surface conduction region linked to Weyl nodes.

Findings

2D conduction path emerges in Co3Sn2S2 thin films.

Surface conduction region estimated at approximately 20 nm thick.

Surface conduction linked to Weyl nodes and Fermi arcs.

Abstract

Two-dimensional (2D) surface of the topological materials is an attractive channel for the electrical conduction reflecting the linearly-dispersive electronic bands. By applying a reliable systematic thickness t dependent measurement of sheet conductance, here we elucidate the dimensionality of the electrical conduction paths of a Weyl semimetal Co3Sn2S2. Under the ferromagnetic phase, the 2D conduction path clearly emerges in Co3Sn2S2 thin films, indicating a formation of the Fermi arcs projected from Weyl nodes. Comparison between 3D conductivity and 2D conductance provides the effective thickness of the surface conducting region being estimated to be approximately 20 nm, which is rather thicker than 5 nm in topological insulator Bi2Se3. This large value may come from the narrow gap at Weyl point and relatively weak spin-orbit interaction of the Co3Sn2S2. The emergent surface conduction will provide a pathway to activate quantum and spintronic transport features stemming from a Weyl node in thin-film-based devices.