Superconducting pairing of spin polarons in the t-J model

TL;DR

This paper demonstrates that in the t-J model, spin polarons form d-wave pairs mediated by spin fluctuations, with a doping-dependent transition temperature that peaks at optimal doping, providing insights into high-temperature superconductivity.

Contribution

The study provides a numerical solution of Eliashberg equations showing d-wave pairing of spin polarons mediated by spin fluctuations in the t-J model, highlighting doping effects on $T_c$.

Findings

d-wave pairing between spin polarons on different sublattices

$T_c$ increases with $J/t$ and peaks at optimal doping

$T_c$ reaches approximately 0.013 t at $ ext{doping} \, \delta_{opt} \simeq 0.2$

Abstract

The pairing of quasiparticles in a CuO$_2$ plane is studied within a spin polaron formulation of the $t$-$t^{'}$-$J$ model. Our numerical solution of the Eliashberg equations unambiguously shows d-wave pairing between spin polarons on different sublattices mediated by the exchange of spin-fluctuations, and a strong doping dependence of the quasiparticle bandwidth. The transition temperature $T_c$ is an increasing function of $J/t$ and crosses a maximum at an optimal doping concentration $\delta_{opt}$. For the t-J model with $J/t=0.4$ we obtain $T_c\simeq 0.013 t$ at $\delta_{opt}\simeq 0.2$.