Effect of Coulomb repulsion on the London penetration depth in cuprate superconductors

Abstract

We study the effect of Coulomb repulsion between oxygen holes on the London penetration depth $\lambda$ based on the concept of spin-polaron nature of Fermi quasiparticles in cuprates superconductors. It is shown that for the generally accepted values of the parameters of the spin-fermion model, taking into account the Coulomb interaction, both the one-site Hubbard $U_p$ and interaction between the holes on next-nearest-neighbor oxygen ions $V_2$, allows one to achieve a much better agreement of the calculated temperature dependencies of the value $\lambda^{-2}$ with the experimental data in La$_{2-x}$Sr$_{x}$CuO$_4$ in a wide range around optimal doping.