| Mean-field theory for the spin-liquid paramagnetic non-superconducting phase of the p- and n-type High-Tc cuprates is developed. This theory applied to the effective t-t'-t''-J* model with the ab initio calculated parameters and with the three-site correlated hoppings. The static spin-spin and kinematic correlation functions beyond Hubbard-I approximation are calculated self-consistently. For p-type systems the three different types of behavior are found and the quantum phase transitions take place at x=0.15 and at x=0.23. The origin of these quantum phase transitions is the doping-dependent change in the Fermi surface topology. Due to the different Fermi surface topology we found for n-type cuprates only one quantum critical concentration, x=0.2. |
|