Two-component model for optical conductivity in Y-Ba-CuO superconductors

The optical conductivity of optimized doped YBa2Cu3O7-delta (delta = 0.0, T -c= 92 K) superconductors, which are frequency dependent, has been theoreti cally investigated based on two-component (Drudel and mid infrared terms) a pproach within the Fermi liquid description. Our approach incorporates the Drude contribution as well as hopping:of charge:carriers in the model: diel ectric function-along with the structure factor. It,explains the anomalies observed-in the optical measurements-for the normal state::as the frequency dependence of optical conductivity using the Drude term which gives a shar p peak at zero,frequency, and a long tail at higher frequencies, i.e. in th e infrared region. The extra term (hopping carriers) gives a peak value in the optical conductivity Centred in the mid infrared region. The two specie s of charge carriers contribution to the conduction in the CuO chain layer as well as CuO layer as well as CuO2 account for the-optical conductivity i n the mid infrared:as well as infrared frequency regions. The analysis reve als an interesting relation sigma(CuO2) layer approximate to 3 sigma (chain layer), and the nature for optical conduction with energy is similar quali tatively, the only difference is quantitatively. It is shown that the analy sis is consistent with the published data on optical conductivity in optimi zed-doped YBa2Cu3O7-delta superconductors.