Ground-state properties of the two-dimensional t-J model

The two-dimensional t-J model in the ground state is investigated by the power Lanczos method. The pairing-pairing correlation function for d_x²-y²-wave symmetry is enhanced in the realistic parameter regime for high-Tc superconductors. The charge susceptibility χc shows divergent behavior as χc{∝}δ^-1 near half filling for the doping concentration {δ}, indicating that the value of the dynamical exponent z is four under the assumption of hyperscaling. The peak height of the spin structure factor Sₘₐₓ(Q) also behaves as Sₘₐₓ(Q){∝}δ^-1 near half filling, which leads to the divergence of the antiferromagnetic correlation length ξₘ as ξₘ{∝}δ^-1/2. The boundary of phase separation is estimated on the basis of the Maxwell construction. Numerical results are compared with experimental features observed in high-Tc cuprates.