Large intrinsic anomalous Hall effect in half-metallic ferromagnet Co3Sn2S2 with magnetic Weyl fermions

Qi Wang,Shancai Wang,Zhonghao Liu,Hongming Weng,Man Li,Yaobo Huang,Yuanfeng Xu,Rui Lou,Dawei Shen,Hechang Lei

doi:10.1038/s41467-018-06088-2

Abstract

The origin of anomalous Hall effect (AHE) in magnetic materials is one of the most intriguing aspects in condensed matter physics and has been a controversial topic for a long time. Recent studies indicate that the intrinsic AHE is closely related to the Berry curvature of occupied electronic states. In a magnetic Weyl semimetal with broken time-reversal symmetry, there are significant contributions to Berry curvature around Weyl nodes, possibly leading to a large intrinsic AHE. Here, we report the quite large AHE in the half-metallic ferromagnet Co3Sn2S2 single crystal. By systematically mapping out the electronic structure of Co3Sn2S2 both theoretically and experimentally, we demonstrate that the intrinsic AHE from the Weyl fermions near the Fermi energy is dominating. The intrinsic anomalous Hall conductivity depends linearly on the magnetization and can be reproduced by theoretical simulation, in which the Weyl nodes monotonically move with the constrained magnetic moment on Co atom.

Highlights

(AHE)[2,3] has attracted tremendous interests because of the fundamental physics and great potential in technical application[4,5], but the microscopic origin of anomalous Hall effect (AHE) is still not fully solved
Our findings suggest the main contribution of observed large AHE originates from the intrinsic mechanism, which is intimately related to the Weyl nodes near EF
A half of Sn atoms lie in the centers of the kagome hexagons (Sn2 sites, Wyckoff position 3a (0, 0, 0)) (Fig. 1b) and another half of Sn atoms located between the Co–Sn bilayers

Summary

Introduction

(AHE)[2,3] has attracted tremendous interests because of the fundamental physics and great potential in technical application[4,5], but the microscopic origin of AHE is still not fully solved. RTophoertoitohnearl to is ρxx, whereas, the side jump intrinsic Kaplus–Luttinger (KL) mechanism related to spin–orbit interaction of Bloch electronic bands, originally proposed by Karplus and Luttinger, which gives ρAxy / ρ2xx[10]. Different from traditional ferromagnets, the HMFMs have attracted extensive interests because of the (nearly) 100% spin polarization of conduction electrons at EF27. They can be perfectly applied to spintronic devices. Our findings suggest the main contribution of observed large AHE originates from the intrinsic mechanism, which is intimately related to the Weyl nodes near EF

Methods

Results

Conclusion