Fermi surface of the Weyl type-II metallic candidate WP2

Abstract

Weyl type-II fermions are massless quasiparticles that obey the Weyl equation and which are predicted to occur at the boundary between electron- and hole-pockets in certain semi-metals, i.e. the (W,Mo)(Te,P)${}_2$ compounds. Here, we present a study of the Fermi-surface of WP${}_2$ \emph{via} the Shubnikov-de Haas (SdH) effect. Compared to other semi-metals WP${}_2$ exhibits a very low residual resistivity, i.e. $\ddot{I}{}_0\simeq 10$ n$\hat{I}\text{c◯}$cm, which leads to perhaps the largest non-saturating magneto-resistivity $(\ddot{I}(H))$ reported for any compound. For the samples displaying the smallest $\ddot{I}{}_0$, $\ddot{I}(H)$ is observed to increase by a factor of $2.5\times 10^7$ $\%$ under $\hat{I}{¼}_{0}H=35$ T at $T=0.35$ K. The angular dependence of the SdH frequencies is found to be in very good agreement with the first-principle calculations when the electron- and hole-bands are slightly shifted with respect to the Fermi level, thus supporting the existence of underlying Weyl type-II points in WP${}_2$.

6 pages, 4 figures, supplementary information not included