Investigation of point-contact Andreev reflection on magnetic Weyl semimetal Co3Sn2S2

Abstract

Magnetic Weyl semimetals (WSMs) with broken time-reversal symmetry (TRS) hosting topological band structures are expected to provide an ideal platform for investigating topological superconductivity and spintronics. However, the experimental verification of magnetic WSMs is very challenging. Very recently, the kagome magnet Co3Sn2S2 was confirmed to be a magnetic WSM by both angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy and consequently has become the focus of great attention. This paper reports a point-contact Andreev-reflection spectroscopy (PCARS) investigation on the (001) surface and the side surface of the Co3Sn2S2 single crystals, respectively. The measurements from the sample’s (001) and side surfaces provide experimental evidence for transport spin polarization in the Co3Sn2S2 magnetic WSM. Furthermore, the superconducting proximity effect in the Co3Sn2S2 single crystal is successfully detected. The point-contact spectra (PCS) along the in-plane direction cannot be well fitted by theoretical models based on s-wave pairing, indicating that possible triplet p-wave superconductivity may be triggered at the interface, which paves the way for the future exploration of the topological superconductivity and Majorana states in broken TRS WSMs.