Charge Transport in Weyl Semimetals

We study transport in Weyl semimetals with N isotropic Weyl nodes in the presence of Coulomb interactions or disorder at temperature T. In the interacting clean limit, we determine the conductivity sigma(omega, T) by solving a quantum Boltzmann equation within a "leading log'' approximation and find it to be proportional to T, up to logarithmic factors arising from the flow of couplings. In the noninteracting disordered case, we compute the Kubo conductivity and show that it behaves differently for omega << T and omega >> T: in the former regime we recover a previous result, of a finite dc conductivity and a Drude width vanishing as NT2; in the latter, we find that sigma(omega, T) vanishes linearly with sigma(omega, T) with a leading term as T -> 0 equal to the clean, free-fermion result: sigma((N))(0)(omega, T = 0) = N e(2)/12h vertical bar omega vertical bar/nu(F). We compare our results to transport data on Y2Ir2O7 and comment on the possible relevance to recent experiments on Eu2Ir2O7.