Intrinsic Berry phase contribution to Hall conductivity in CoS2

In Weyl semimetals, the conduction and valence bands intersect at distinct points on the Brillouin zone (Weyl points), which act as monopoles of Berry curvature in momentum space. This nontrivial band topology, identified from electronic structure calculations, gives rise to various exotic magnetotransport properties. Hybrid functional calculations that incorporate a portion of exact exchange, magnetotransport measurements, and temperature-dependent resistivity confirm nontrivial band topology and half-metallicity in CoS₂ of magnetic ordering temperature TC≈1283.33333pt0exK. However, electronic structure calculations also show that application of small strain transforms this half metallic character to the metallic. Interestingly, the magnetoresistance (MR) of the CoS₂ films at low fields and T≤604.pt0exK is suggestive of weak localization. The MR changes signs from negative to positive value as the T goes from <TC to >TC. Experimental observation of anomalous Hall resistivity and ab initio computed band structure, Berry curvature, and Hall conductivity (σxy) demonstrate that the σxy in CoS₂ is primarily driven by the intrinsic Karplus-Luttinger contribution, often linked to Berry phase physics.