Epitaxial growth and transport properties of magnetic Weyl semimetal Co3Sn2S2 thin films

Abstract

Shandite type Co3Sn2S2 has been reported as a magnetic Weyl semimetal recently and predicted to realize the quantum anomalous Hall effect in a two-dimensional limit. So far, electron transport studies were mostly conducted on bulk crystals, while ultrathin Co3Sn2S2 films are desirable for further gate-tunable studies and device applications. Here, we report the molecular beam epitaxy growth of Co3Sn2S2 thin films with thickness as thin as 18 nm on SrTiO3(111) substrates. Compelling characterizations indicate the high quality of the thin film. In addition to much larger coercive fields, the Co3Sn2S2 thin film also allow for the observation of pronounced hysteresis in the magnetoresistance, which was barely noticeable in the bulk samples. Furthermore, we show that the anomalous Hall conductivity can be varied by more than 2 orders of magnitude by adjusting the growth conditions of the Co3Sn2S2 thin films. Our studies suggest a feasible approach to fabricate highly tunable Co3Sn2S2 thin films for further exploration of their unique electronic properties.