In-plane Antiferromagnetism in Ferromagnetic Kagome Semimetal Co3Sn2S2

Abstract

Co3Sn2S2 has been reported to be a Weyl semimetal with broken time-reversal symmetry with c axis ferromagnetism (FM) below a Curie temperature of 177 K. Despite the large interest in Co3Sn2S2, the magnetic structure is still under debate and recent studies have challenged our understanding of the magnetic phase diagram of Co3Sn2S2 by reporting unusual magnetic phases including the presence of exchange bias. Understanding the magnetism of Co3Sn2S2 is important since its electronic band structure including the much-celebrated flat bands and Weyl nodes depend on the magnetic phase. In this work, using X-ray Magnetic Circular Dichroism (XMCD), we establish that the magnetic moment in Co arises from the spin, with negligible orbital moment. In addition, we detect an in-plane AFM minority phase in the sea of a FM phase using spatially-resolved angle-resolved photoemission spectroscopy (μ-ARPES) combined with density functional theory (DFT) calculation. Separately, we detect a sharp flat band precisely at the Fermi level (EF) at some regions in the sample, which we attribute to a surface state. The AFM phase survives even to the low temperature of 6 K. This example of entirely different magnetic ground states in a stoichiometric intermetallic invites further efforts to explore the observed AFM phase and understand the origin and nature of the magnetic and electronic inhomogeneity on the mesoscale and the interface between the AFM and FM phases.

References in corpus (12)

• Negative flat band magnetism in a spin-orbit coupled correlated kagome magnet
• Unusual exchange couplings and intermediate temperature Weyl state in Co3Sn2S2
• Electronic structure and topology across $T_c$ in magnetic Weyl semimetal Co${}_3$Sn${}_2$S${}_2$
• Putative helimagnetic phase in the kagome metal Co_3Sn_2-xIn_xS_2
• The magnetic structure of the topological semimetal Co${}_3$Sn${}_2$S${}_2$
• Electric quadrupole second harmonic generation revealing dual magnetic orders in a magnetic Weyl semimetal
• Hidden spin-texture at topological domain walls drive exchange bias in a Weyl semimetal
• Topological Quasi-2D Semimetal Co${}_3$Sn${}_2$S${}_2$: Insights To Electronic Structure From NEXAFS and Resonant Photoelectron Spectroscopy
• Spin structure and dynamics of the topological semimetal Co${}_3$Sn${}_{2-x}$In${}_x$S${}_2$
• Anomalous depinning of magnetic domain walls within the ferromagnetic phase of the Weyl semimetal Co3Sn2S2
• Unravelling the origin of the peculiar transition in the magnetically ordered phase of the Weyl semimetal Co3Sn2S2
• Magnetic Breakdown and Chiral Magnetic Effect at Weyl-Semimetal Tunnel Junctions