Infrared properties of cuprates in the pseudogap state: A study of   Mitrovic-Fiorucci and Sharapov-Carbotte scattering rates
  Frequency dependent scattering rate of generalized Drude model contains important physics of the electronic structure and of scattering mechanisms. In the present investigation, we study the frequency dependent scattering rate of cuprates (Mitrovic-Fiorucci/ Sharapov-Carbotte scattering rate) in the pseudogap phase using the non-constant energy dependent Yang-Rice-Zhang (YRZ) density of states. First, with the energy dependent density of states, the scattering rate gives the picture of depression formation coming from the opening of the pseudogap. Second, the evolution of $1/\tau(\omega)$ with temperature shows the increase of scattering rate with the temperature at lower frequencies and the temperature independence of $1/\tau(\omega)$ at higher frequencies. Third, the signature of thresholds due to boson density of states and the electronic density of states also has been observed. These signatures are qualitatively in accord with the experiments. 
Pankaj Bhalla and Navinder Singh
cond-mat.supr-con cond-mat.str-el