Origin of the hump structure in the in-plane optical conductivity of high-TC cuprates based on a SU(2) slave-boson theory

An improved version of the SU(2) slave-boson approach is applied to study the in-plane optical conductivity of the two dimensional systems of high-TC cuprates. We investigate the role of fluctuations of both the phase and amplitude of order parameters on the (Drude) peak-dip-hump structure in the in-plane conductivity as a function of hole doping concentration and temperature. The mid-infrared (MIR) hump in the in-plane optical conductivity is …