Projected Wavefunctions and High T c Superconductivity in Doped Mott Insulators

Abstract

We review the use of projected wavefunctions to gain insight into the strongly correlated d-wave superconducting state of high T c cuprates within the framework of the large U Hubbard model. Using sum rules, we show that doped Mott insulators exhibit a strong particle-hole asymmetry in their single-particle spectral function. We calculate the doping dependence of a variety of observables using a simple approximation scheme, the Gutzwiller approximation, and compare the results with variational Monte Carlo results and with experimental data on the cuprates. We gain detailed insights into the superconducting dome, the energy gap, nodal excitations, their quasiparticle weight and dispersion, momentum distribution, superfluid stiffness, and optical spectral weight. We show that strong correlations make the d-wave state robust against disorder-induced pair breaking. Finally, we discuss the competition between antiferromagnetism and superconductivity, the difference between hole and electron-doped Mott insulators, and how the range of hopping enhances superconductivity for hole-doped materials.