On the Optical Properties in Nesting Fermi Liquid

One of the most common and prominent optical features of high temperture supeconductors is the quadratic frequence of the loss function, i.e., Im(-1/ε)=βω², for ħω ≤1eV.We show that the nesting Fermi liquid (NFL) theory can quantitatively account for the low frequency(<0.5eV) behavior, but it can not explain the higher frequency behavior. This suggests that the form of relaxation rate derived from the NFL is inadequate to describe the high frequency behavior in high temperature superconductors