Stability of the Superconducting d-Wave Pairing Toward the Intersite Coulomb Repulsion in CuO2 Plane

Val'kov, VV; Dzebisashvili, DM; Korovushkin, MM; Barabanov, AF JOURNAL OF LOW TEMPERATURE PHYSICS, 191 (5-6):408-425; SI 10.1007/s10909-018-1882-7 JUN 2018

Taking into account the real crystalline structure of the ${CuO}_{2}$ plane and the strong spin-fermion coupling, we study the influence of the intersite Coulomb repulsion between holes on the Cooper instability of the spin-polaron quasiparticles in cuprate superconductors. The analysis shows that only the superconducting d-wave pairing is implemented in the whole region of doping, whereas the solutions of the self-consistent equations for the s-wave pairing are absent. It is shown that intersite Coulomb interaction $V_{1}$ between the holes located at the nearest oxygen ions does not affect the d-wave pairing, because its Fourier transform $V_{q}$ vanishes in the kernel of the corresponding integral equation. The intersite Coulomb interaction $V_{2}$ of quasiparticles located at the next-nearest oxygen ions does not vanish in the integral equations, however, but it is also shown that the d-wave pairing is robust toward this interaction for physically reasonable values of $V_{2}$ .