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 (alpha pocket) and 15.6 T (beta pocket). The analysis, including a Landau fan plot, shows that the beta pocket has a Berry phase of pi and a small effective mass of similar to 0.033 m(0), indicative of a nontrivial topology in momentum space, whereas the a pocket has a trivial Berry phase of 0 and a heavier effective mass of similar to 0.066 m(0). From the effective mass and the beta-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.