de Haas-van Alphen oscillations and anomalous Hall effect in topological nodal line semimetal Ni 0.5 Co 0.5 Se

Abstract Here, we present a systematic study of de Haas-van Alphen oscillations (dHvAs), topological phase, and anomalous Hall effect (AHE) of Ni 0.5 Co 0.5 Se single crystal. Low-temperature longitudinal resistivity ρ xx ( T ) under different magnetic fields exhibits an upturn, indicative of a semimetallic phase. Fitting of the zero-field ρ xx ( T ) data with the Bloch–Gruneisen–Mott model including Kondo resistivity term reveals multiple scattering mechanisms, which is substantiated by the deviation from Kohler’s rule of the magnetoresistance curves. At T = 2 K and low magnetic fields, the observed cusp-like features indicate weak antilocalization effect, quantitatively described using a modified Hikami–Larkin–Nagaoka equation. Temperature dependent magnetization ( M – T ) curves and magnetic field dependent isothermal magnetization ( M – B ) curves reveal the existence of weak ferromagnetic phase at very low temperatures. The weak field magnetoconductivity data follows the - ln ( B ) dependency and the observed strong high field dHvA oscillations in ( M – B ) curves, provide the evidence of non-zero Berry phase, confirms the non-trivial band topology. These signatures indicate that Ni 0.5 Co 0.5 Se is a topological nodal line semimetal. In Hall resistivity data, significant AHE is observed at 2 K to 5 K and the linear behavior of the anomalous Hall resistivity ( ρ x y A ) with ρ xx signifies that the extrinsic skew scattering mechanism contributes to AHE in Ni 0.5 Co 0.5 Se.