Fermi surface and field-induced Lifshitz transition in the antiferromagnet NbMnP exhibiting an anomalous Hall effect

We performed Shubnikov--de Haas (SdH) oscillation measurements on the $\mathbf{Q}=0$ antiferromagnet NbMnP, which exhibits a large anomalous Hall effect. The SdH frequencies observed in the low-field region up to 17.5~T are well described by first-principles band-structure calculations based on the $B_{3g}+B_{2u}$ noncollinear magnetic structure determined by neutron diffraction. The effective masses are enhanced by approximately a factor of two relative to the calculated band masses. High-field measurements up to 41.5~T reveal a Lifshitz transition accompanied by a pronounced evolution of the SdH frequency spectrum. These results confirm that first-principles calculations provide a reliable tool for the development of functional antiferromagnetic materials, while also demonstrating that field-induced changes in the Fermi surface itself need to be taken into account in understanding their high-field magnetotransport properties.