Transport properties in thed-density wave state: Wiedemann–Franz Law

Abstract

We study the Wiedemann–Franz (WF) law in the d-density wave (DDW) model. Even though the opening of the DDW gap ${(W}_0)$ profoundly modifies the electronic density of states and makes it dependent on energy, the value of the WF ratio at zero temperature $\mathrm{}(T=0\mathrm{})\mathrm{}$ remains unchanged. However, neither electrical nor thermal conductivity display universal behavior. For finite temperature, with T greater than the value of the impurity scattering rate at zero frequency $\gamma \mathrm{}\left(0\right),$ i.e., $\gamma \mathrm{}\left(0\right)<T\ll W_0,$ the usual WF ratio is obtained only in the weak scattering limit. For strong scattering there are large violations of the WF Law.