Evidence for Undoped Weyl Semimetal Charge Transport in $Y_{2}I{r}_2{O}_7$

Abstract

Weyl fermions scattering from a random Coulomb potential are predicted to exhibit resistivity versus temperature $\ddot{I}\hat{I}\pm T^{-4}$ in a single particle model. Here we show that, in closed environment-grown polycrystalline samples of $Y_{2}I{r}_2{O}_7$, $\ddot{I}=\ddot{I}{}_0{T}^{-4}$ over four orders of magnitude in $\ddot{I}$. While the measured prefactor, $\ddot{I}{}_0$, is obtained from the model using reasonable materials parameters, the $T^{-4}$ behavior extends far beyond the model's range of applicability. In particular, the behavior extends into the low-temperature, high-resistivity region where the Ioffe-Regel parameter, $k_T\ell \ll 2\ddot{I}€$. Strong on-site Coulomb correlations, instrumental for predicting a Weyl semimetal state in $Y_{2}I{r}_2{O}_7$, are the possible origin of such "bad" Weyl semimetal behavior.

12 pages, 3 figures