Renormalized mean-field t−J model of high-Tc superconductivity: Comparison to experiment

Abstract

Using an advanced version of the renormalized mean-field theory for the t-J model, we examine the spin-singlet superconducting (SC) state of dx2−y2 symmetry. Overall doping dependence of the SC gap magnitude is in good agreement with experimental results for Bi2Sr2CaCu2O8+δ and La2−xSrxCuO4 compounds at the optimal doping and in the overdoped regime. We also calculate the dispersion relation for the Bogoliubov quasiparticles and compare our findings both with the angle-resolved photoemission data for the cuprates as well as with the variational Monte Carlo and other mean-field studies. Within the method proposed by Fukushima [Phys. Rev. B 78, 115105 (2008)], we analyze different forms of the t-J Hamiltonian, i.e., modifications caused by the form of exchange interaction, and by the presence of three-site terms. It is shown that although the former has a small influence, the latter suppresses strongly the superconductivity. We also analyze the temperature dependence of the gap magnitude and compare the results with those of the recently introduced finite-temperature renormalized mean-field theory of Wang et al. [Phys. Rev. B 82, 125105 (2010)].

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