Journal Article

Inhomogeneity in electronic phase and flat band in magnetic kagome metal Co3Sn2S2

Plokhikh, Igor, Okamoto, Satoshi, Tamai, Anna, Soh, Yona, Dreiser, Jan, Roduit, Loïc, Gawryluk, Dariusz Jakub, Ekahana, Sandy Adhitia, Hunter, Andrew

2025

Overview

Co 3 Sn 2 S 2 has been reported to be a Weyl semimetal with c -axis ferromagnetism below a Curie temperature of 177 K. Despite the large interest in Co 3 Sn 2 S 2 , the magnetic structure is still unclear. Recent studies have challenged the magnetic phase diagram of Co 3 Sn 2 S 2 by reporting unusual magnetic phases including the presence of exchange bias. Here we show, using X-ray Magnetic Circular Dichroism, a shift in the magnetization hysteresis loop, reminiscent of exchange bias and establish that the magnetic moment in Co arises from the spin, with negligible orbital moment. At 6 K, using spatially-resolved angle-resolved photoemission spectroscopy, we detect a butterfly-shaped electronic band structure at small regions of the sample distinct from the known ferromagnetic band structure. Our density functional theory calculations suggest that the butterfly bands correspond to an antiferromagnetic phase. Separately, we detect a sharp flat band at the Fermi level at some regions in the sample, which we attribute to a surface state. These different electronic states found in a stoichiometric intermetallic invite further efforts to explore the origin and nature of the electronic inhomogeneity associated to magnetism on the mesoscale. Co ₃ Sn ₂ S ₂ has been reported to be a Weyl semimetal but its magnetic and electronic structure is still under debate. Here, X-ray magnetic circular dichroism reveals that cobalt magnetic moments originate from spin, rather than orbital moments, whereas spatially-resolved angle-resolved photoemission spectroscopy indicates the presence of electronic inhomogeneities in the band structure and magnetic phases.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Springer Nature,Nature Portfolio
• Subject: 639/301/119/995 / 639/766/119/997 / Antiferromagnetism / Band structure of solids / Band theory / Banded structure / Bias / Chemistry and Materials Science / Crystal structure / Curie temperature / Density functional theory / Dichroism / Electron states / Electronic properties and materials / Electronic structure / Electrons / Ferromagnetism / Hysteresis loops / Indium / Inhomogeneity / Magnetic fields / Magnetic moments / Magnetic properties and materials / Magnetic structure / Materials Science / Phase diagrams / Photoelectric emission / Photoelectron spectroscopy / Temperature