Optimized wave function by kinetic renormalization effect in strongly correlated region of the three-band Hubbard model

We investigate the ground state of the two-dimensional single-band Hubbard model and three-band Hubbard model (d-p model) by using a variational Monte Carlo method. We employ an optimization variational Monte Carlo method. In this method the many-body wave function is improved and optimized by introducing variational parameters in the form: psi = exp(-S)psi(0) where psi(0) is a wave function, for example, the Gutzwiller function, and S is an operator used to include the many-body effect. The strong magnetic correlation is induced by the on-site Coulomb repulsive interaction U. The magnetic correlation plays a significant role in correlated electron systems as an origin of electron pairing as well as a main competitor of superconductivity. High-temperature superconductivity occurs in the strongly correlated region where U is greater than the bandwidth. We investigate the stability of antiferromagnetic state in the three-band d-p model.