Breakdown of the universality of the Kadowaki-Woods Ratio in multi-band metals

We calculate the Kadowaki-Woods ratio (KWR) in Fermi liquids with arbitrary band structures. We find that, contrary to the single-band case, the ratio is not generally independent of the effects of electronic correlations (universal). This is very surprising given the experimental findings of a near universal KWR in many multiband strongly correlated metals. We identify a limit where the universality of the ratio is recovered. We discuss the KWR in Dirac semimetals and find that the KWR is independent of correlations, but strongly dependent on the doping of the system: for massless fermions, the KWR is proportional to the inverse square of the carrier density.