Effective potential and superconductivity in copper oxide superconductors

The layered electron gas (LEG) model has been used to calculate the effective potential (using three types of 2D polarizability which are based on tight binding approximation, random phase approximation and marginal Fermi liquid approxiation) for cuprate superconductors which consist of one and two Cu-O layers per unit cell, respectively. The calculated effective potential has then been averaged over wave vector and a comparative study of effective potentials is made. It is noticed that the calculated effective potentials using polarizabilities based on tight binding approximation and marginal Fermi liquid approximation give comparatively better descriptions of cuprate superconductors. The possible use of our calculated effective potential to compute Tc for superconductors has been suggested. It is found that the net attractive effective potential can be obtained within the LEG model for q (a-b plane component of the wave vector) smaller than one-tenth of the Fermi wave vector. (orig.)