c-Axis Optical Reflectivity of Layered Cuprate Superconductors

Using a conventional BCS–Fermi liquid model we calculate the $c$-axis optical reflectivity of the layered high temperature cuprate superconductors by obtaining the finite temperature dynamical dielectric function in a microscopic self-consistent gauge invariant formalism. We get good semiquantitative agreement with all the existing experimental data by using the measured normal state dc resistivities as the input parameters in obtaining the $c$-axis hopping amplitude and the normal state level broadening in our microscopic calculation.