Electron-hole compensation effect between topologically trivial electrons and nontrivial holes in NbAs

Via angular Shubnikov--de Haas (SdH) quantum oscillations measurements, we determine the Fermi surface topology of NbAs, a Weyl semimetal candidate. The SdH oscillations consist of two frequencies corresponding to two Fermi surface extrema: 20.8 T (α pocket) and 15.6 T (β pocket). The analysis, including a Landau fan plot, shows that the β pocket has a Berry phase of π and a small effective mass of ~0.0334pt0exm₀, indicative of a nontrivial topology in momentum space, whereas the α pocket has a trivial Berry phase of 0 and a heavier effective mass of ~0.0664pt0exm₀. From the effective mass and the β-pocket frequency, we determine that the Weyl node is 110.5 meV from the chemical potential. An electron-hole compensation effect is discussed in this system, and its impact on magnetotransport properties is addressed. The difference between NbAs and other monopnictide Weyl semimetals is also discussed.