Enhancement of pairing correlation by t′ in the two-dimensional extended t-J model -: art. no. 227002

We investigate the effects of the next-nearest-neighbor (t') and the third-nearest-neighbor (t") hopping terms on superconductivity correlation in the 2D hole-doped extended t-J model based on the variational Monte Carlo, mean-field calculation and exact diagonalization method. Despite the diversity of the methods employed, the results all point to a consistent conclusion: While the d-wave superconductivity correlation is slightly suppressed by t' and t"(') in underdoped regions, it is greatly enhanced in the optimal and overdoped regions. The optimal T-c is a result of the balance of these two opposite trends.