Does Simple Two-Dimensional Hubbard Model Account for High-TcSuperconductivity in Copper Oxides?
Takeshi Aimi, Masatoshi Imada
We reexamine whether the essence of high-Tc superconductivity is contained in doped Hubbard models on the square lattice by using recently developed pre-projected Gaussian-basis Monte Carlo method. The superconducting correlations of the dx2-y2 wave symmetry in the ground state at distance r decays essentially as inverse cubic of r. The upper bound of the correlation at long distances estimated by this unbiased method is 0.001, indicating that recent extensions of dynamical mean-field theories and variational methods yielded at least an order of magnitude overestimates of it. The correlations are too weak for the realistic account of the cuprate high-Tc superconductivity.
arXiv:0708.3416•Journal of the Physical Society of Japan•Nov 12, 2007•106 citations