Role of CuO chains on the supercurrent density in bilayer cuprate superconductors

In the present paper, we study the role of CuO-chains on supercurrent density in bilayered cuprate superconductors. For this purpose, a tight binding model Hamiltonian that includes various intra and inter-bilayer interactions along with contributions of Josephson-like tunneling of Cooper pairs from bilayer of CuO2 planes to CuO-chains and vice-versa as well as single particle hopping between CuO2 bilayer to CuO-chains in the form of the bilayer chain interaction within a unit cell is considered. The situation considered here is equivalent to a Josephson's coupled SNS junction. In the superconducting state, the CuO2 bilayer serves as superconducting electrode and CuO-chains as one dimensional metal under fully oxygenated overdoped state sandwitched between these two electrodes as in the case of YBa2Cu3O7 bilayer system and there is always a possibility of Cooper pairs to tunnel from one bilayer CuO2 planes to other bilayer via CuO-chains. To derive the expressions for the superconducting order parameter, carrier density and supercurrent density, we rely on mean-field Green's function equations of motion calculations within the BCS formalism. The numerical calculations show that in bilayer cuprates, the supercurrent density depend on the interlayer pair tunneling between the CuO2 planes, hopping matrix element (tch) for chains and the hopping of single particle from bilayer to chains. Finally, we have compared these results with the existing experimental findings. (author)