Optical response for the d-density-wave model -: art. no. 134503

We have calculated the optical conductivity and the Raman response for the d-density-wave model, proposed as a possible explanation for the pseudogap seen in high T-c cuprates. The total optical spectral weight remains approximately constant on opening of the pseudogap at fixed temperature. This occurs because there is a transfer of weight from the Drude peak to interband transitions across the pseudogap. The interband peak in the optical conductivity is prominent but becomes progressively reduced with increasing temperature; with impurity scattering, which distributes it over a larger energy range; and with inelastic scattering, which can also shift its position, making it difficult to have a direct determination of the value of the pseudogap. Corresponding structure is seen in the optical scattering rate, but not necessarily at the same energies as in the conductivity.