Giant anomalous Hall and planar Hall effect in magnetic Weyl semimetal Co₃Sn₂S₂ nanoflakes

Weyl fermions are chiral massless fermions manifested in crystalline solids by spin split conduction and valence bands crossing at discrete points. Magnetic Weyl semimetals with spontaneous time-reversal-symmetry-breaking are predicted to host large Berry curvature and resulting in a large intrinsic anomalous Hall effect (AHE). In this work, we perform detailed transport studies on the nanoflake devices of magnetic Weyl semimetal, Co₃Sn₂S₂. The two-dimensional nature of its Kagome-lattice allows Co₃Sn₂S₂ to be grown into nanoflakes as thin as 180 nm via the chemical vapor transport method. Through magneto-transport measurements, we observe a large intrinsic anomalous Hall conductivity (AHC) and anomalous Hall angle (AHA) generated by the Weyl-related Berry curvature that is robust against both temperature and charge conductivity. The AHC and AHA simultaneously reach 1422 S/cm and 23%, even higher than recent reports in single crystals [1]. Furthermore, we discuss the observation of the planar Hall effect (PHE) in Co₃Sn₂S₂ which can be caused by the chiral anomaly. Other possible origins of the PHE, including contributions from orbital magnetoresistance and interaction of the electrons with the magnetic order will also be discussed.

[1] Liu, E., et al., Nature Physics, 2018: p. 1.