Influence of intersite Cu-O repulsion on hole binding and pairing correlations in the three-band Hubbard model

摘要

The hole binding energy and pairing correlations are calculated in the three-band Hubbard model by using the constrained-path Monte Carlo (CPMC) method. In the physically relevant region, we investigated effects of Ca - O Coulomb repulsion V-pd on these two properties. Simulations were performed on lattices of 2x2, 4x2, and 6x4 unit cells. For the 2x2 unit cell, the CPMC results are in good agreement with exact diagonalization results. For it we found that the hole binding energy clearly increases with the nearest-neighbor Coulomb repulsion Vpd, but for larger systems it increases only slightly. For the:extended s-wave channel, we found that the pairing correlations and vertex contributions increase slightly with an increase of V-pd, while for the d(x2-y2)-wave channel both tend to decrease. [References: 6]