Interplay of single particle and Josephson Cooper pair tunnelings on the electronic spectra of bilayer cuprate superconductors

We have investigated the interplay of single particle and Josephson Cooper pair tunnelings on the electronic spectra of optimal and overdoped bilayer cuprate (Bi2Sr2CaCu2O8+x) superconductors using tight binding bilayer Hubbard Hamiltonian within BCS d-wave superconducting state. On the basis of the numerical computation of the spectral function at (π, 0) point of the Brillouin zone, a reduction in bilayer splitting energy is pointed out due to the existence of Josephson Cooper pair tunneling in the superconducting state. We have explained our theoretical analysis of the spectral function in the light of recent angle resolved photoemission spectroscopic (ARPES) measurements on optimal doped bilayer cuprates, where a reduction in the bilayer splitting energy is observed in the superconducting state as compared to normal state.