Breakdown of Ohm’s law and nontrivial Berry phase in magnetic Weyl semimetal Co3Sn2S2

Abstract

The concept of realization of Weyl points close to the Fermi level in materials with broken time-reversal symmetry has significant theoretical and technological ramifications. Here, we review the investigation of magneto-transport measurements in single crystals of magnetic Weyl semimetal Co3Sn2S2. We see a turn-on like behaviour followed by saturation in resistivity under magnetic field in the low temperature region which is allocated to the topological surface states. A non-saturating magnetoresistance, linear at high fields, is observed at low temperatures where applied magnetic field is transverse to the current direction. The linear negative magnetoresistance at low magnetic fields (B < 0.1 T) provides evidence for time reversal symmetry breaking in Co3Sn2S2. Chiral anomaly in Weyl metallic state in Co3Sn2S2 is confirmed from the breakdown of Ohm’s law in the electronic transport. Shubnikov de Haas (SdH) oscillation measurement has unveiled the multiple sub-bands on the Fermi surface that corresponds to a non-trivial Berry phase. The non-linear behaviour in Hall resistivity validates the existence of two type of charge carriers with equal electron and hole densities. Strong temperature dependence of carrier mobilities reflects the systematic violation of Kohler’s rule in Co3Sn2S2. Our findings open avenues to study kagome-lattice based magnetic Weyl semimetals that unfurl the basic topological aspects leading to significant ramification for spintronics.