Evidence for undoped Weyl semimetal charge transport in Y₂Ir₂O₇

Weyl fermions scattering from a random Coulomb potential are predicted to exhibit resistivity versus temperature [Formula: see text] in a single particle model. Here we show that, in closed-environment-grown polycrystalline samples of Y₂Ir₂O₇, [Formula: see text] over four orders of magnitude in [Formula: see text]. While the measured prefactor, [Formula: see text], is obtained from the model using reasonable materials parameters, the [Formula: see text] 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, [Formula: see text]. Strong on-site Coulomb correlations, instrumental for predicting a Weyl semimetal state in Y₂Ir₂O₇, are the possible origin of such 'bad' Weyl semimetal behavior.