Nonsaturating Magnetoresistance and Nontrivial Band Topology of Type-II Weyl Semimetal NbIrTe4

Weyl semimetals, characterized by nodal points in the bulk and Fermi arc states on the surface, have recently attracted extensive attention due to their potential application as materials for low-energy-consumption electronics. The thermodynamic and transport properties of a theoretically predicted Weyl semimetal NbIrTe4 is measured in high magnetic fields up to 35 T and low temperatures down to 0.4 K. Remarkably, NbIrTe4 exhibits a nonsaturating transverse magnetoresistance that follows a power-law dependence in B. Low-field Hall measurements reveal that hole-like carriers dominate the transport for T > 80 K, while the significant enhancement of electron mobilities obtained by lowering T results in a non-negligible contribution from electron-like carriers, which is responsible for the observed nonlinear Hall resistivity at low T. The Shubnikov-de Haas oscillations of the Hall resistivity under high B give the light effective masses of charge carriers and the nontrivial Berry phase associated with Weyl fermions. Further first-principles calculations confirm the existence of 16 Weyl points located at k(z) = 0, +/- 0.02, and +/- 0.2 planes in the Brillouin zone.