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

TL;DR

This study uses quantum oscillations to map the Fermi surface of NbAs, revealing a coexistence of trivial electrons and nontrivial holes, and discusses how electron-hole compensation influences its magneto-transport properties.

Contribution

It provides the first detailed Fermi surface topology of NbAs, identifying trivial and nontrivial pockets and analyzing their effects on electron-hole compensation.

Findings

Identification of trivial and nontrivial Fermi pockets

Determination of Weyl node proximity to the chemical potential

Discussion of electron-hole compensation effects on transport

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 ($\alpha$-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 $\sim$0.033 $m_0$, indicative of a nontrivial topology in momentum space; whereas the $\alpha$-pocket has a trivial Berry phase of 0 and a heavier effective mass $\sim$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. 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.