Dr. LIU Enke and Prof. Claudia Felser et al. from Max Planck Institute for Chemical Physics of Solids in Germany found that Co₃Sn₂S₂, a magnetic Weyl semimetal with a quasi 2-dimensional Kagome lattice, displays an intrinsic giant anomalous Hall effect. And their discovery was published in Nature Physics.

A portion of this work was performed on the Steady High Magnetic Field Facilities (SHMFF), High Magnetic Field Laboratory.

A high temperature quantum anomalous Hall effect is very important for novel computing technologies including quantum computing. And it is possible to be achieved in magnetic Weyl semimetals with the Weyl nodes close to the Fermi energy in energy.

However, no ideal candidate has been found before.

Co₃Sn₂S₂, a Shandite compound, possesses a quasi-2D Co₃Sn layer sandwiched between sulfur atoms, with the magnetic cobalt atoms arranged on a kagome lattice and the magnetic moment along the out of plane direction.

In this work, Co₃Sn₂S₂ was found to display a giant anomalous Hall effect and a giant Hall angle (an order of magnitude larger than typical magnetic systems) at temperatures of up to 150 K suggestive of a Weyl semimetal.

Band structure calculations show that the Weyl nodes are located just 60 meV above the Fermi level. Magnetotransport measurements give an evidence for the chiral anomaly that is a clear signature of a Weyl semimetal.

Then Shubnikov-de Haas (SdH) quantum oscillations were observed in higher magnetic field in SHMFF, showing magnetotransport properties of magnetic Weyl semimetals and confirming the band structure calculations.

This is the first material that hosts both a large anomalous Hall conductivity and a giant anomalous Hall angle that originate from the Berry curvature of the topological Weyl phase, providing a clear path to the observation of a quantum anomalous hall effect at room temperature by exploring families of magnetic Weyl semimetals.

SHMFF Serves as one of the national major scientific and technological infrastructure projects of China to provide global users a wide range of user facilities and services for multi-disciplinary and cross-disciplinary researches under steady high magnetic fields.

SdH oscillations in Co₃Sn₂S₂ observed in static high magnetic field and effective mass evaluation calculated from the results. (Image by the research team)