Thermodynamic properties of the t-J-U model in the context of high-Tc cuprates

Some thermodynamic properties of the high-Tc cuprates have been studied using t-J-U model at different doping () by an exact method on a tilted square cluster. Low temperature specific heat curves show single-peak structure where the peak-height decreases with increasing . The system becomes more disordered with decreasing hole occupancy. The extrapolation of all reciprocal susceptibility (χ-1) curves intercept at a negative temperature ΘN which suggests an antiferromagnetic correlation in the system.