Extremely large magnetoresistance and chiral anomaly in the nodal-line semimetal ZrAs2

Abstract: We performed the detailed magnetotransport measurements and first principle calculations to study the electronic properties of the transition metal dipnictides ZrAs2, which is a topological nodal-line semimetal. Extremely large unsaturated magnetoresistance (MR) which is up to 1.9 * 10^4 % at 2 K and 14 T was observed with magnetic field along the c-axis. The nonlinear magnetic field dependence of Hall resistivity indicates the multi-band features, and the electron and hole are nearly compensated according to the analysis of the two-band model, which may account for the extremely large unsaturated MR at low temperatures. The evident Shubnikov-de Haas (SdH) oscillations at low temperatures are observed and four distinct oscillation frequencies are extracted. The first principle calculations and angle-dependent SdH oscillations reveal that the Fermi surface consists of three pockets with different anisotropy. The observed twofold symmetry MR with electric field along the b-axis direction is consistent with our calculated Fermi surface structures. Furthermore, the negative magnetoresistance (NMR) with magnetic field in parallel with electric field is observed, which is an evident feature of the chiral anomaly.