Evidence for undoped Weyl semimetal charge transport in Y₂Ir₂O₇

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