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

Abstract

Via angular Shubnikov-de Hass (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 ($\hat{I}\pm$-pocket) and 15.6 T (${\hat{I}}^2$-pocket). The analysis, including a Landau fan plot, shows that the ${\hat{I}}^2$-pocket has a Berry phase of $\ddot{I}€$ and a small effective mass $\sim$0.033 $m_0$, indicative of a nontrivial topology in momentum space; whereas the $\hat{I}\pm$-pocket has a trivial Berry phase of 0 and a heavier effective mass $\sim$0.066 $m_0$. From the effective mass and the ${\hat{I}}^2$-pocket frequency we determine that the Weyl node is 110.5 meV from the chemical potential. A novel electron-hole compensation effect is discussed in this system, and its impact on magneto-transport properties is addressed. The difference between NbAs and other monopnictide Weyl semimetals is also discussed.

8 pages, 6 figures, 1 table