Enhancement of superconducting transition temperature by the additional second neighbor hopping t′ in the t-J model

Within the kinetic energy driven superconducting mechanism, the effect of the additional second neighbor hopping t′ on the superconducting state of the t-J model is discussed. It is shown that t′ plays an important role in enhancing the superconducting transition temperature of the t-J model. It is also shown that the superconducting-state of cuprate superconductors is the conventional Bardeen-Cooper-Schrieffer like, so that the basic Bardeen-Cooper-Schrieffer formalism is still valid in quantitatively reproducing the doping dependence of the superconducting gap parameter and superconducting transition temperature, and electron spectral function at [π,0] point, although the pairing mechanism is driven by the kinetic energy by exchanging dressed spin excitations.