Low-hole doping regime of the t-J model: Possible microscopic scenario for cuprates

The results of an extensive investigation of photoemission spectral weight using electronic models for the high-Tc superconductors are reviewed. Some recently reported unusual features of the cuprates namely the presence of (i) flat bands, (ii) antiferromagnetically induced weight, and (iii) small quasiparticle bandwidths have all a natural explanation within the context of holes moving in the presence of robust antiferromagnetic correlations. An effective Hamiltonian, Heff, for dressed holes in antiferromagnets is constructed from numerical studies of the 2D t-J model. Once J/t is fixed, Heff has no additional free parameters. The dominant superconducting instability appears in the dx2-y2 channel, with a critical temperature of about 100K at the open-quotes optimalclose quotes hole doping of 15%. The ratio 2Δ/kTc agrees with tunneling data. Calculations of the specific heat jump, mean Cooper-pair radius and other key properties are in good agreement with recent experiments as well. The quasiparticle lifetime vs frequency is nearly linear at the optimal doping. The van-Hove singularity in this model is due to strong correlations and not much sensitive to the higher order corrections or the introduction of disorder