Some finite temperature characteristics of the high-T_c cuprates within t-J-U model

The effects of nearest-neighbor (NN) antiferromagnetic (AF) exchange interaction (J) and temperature on high-Tc cuprates have been studied using an eight-site frustrated t-J-U model. Average hole density is taken as <h> = 0.25, appropriate for cuprates. Above a critical temperature, local moment decreases with temperature but increases with J/t. Corresponding double occupancy shows the reverse character. The system becomes more disordered with NN AF interaction. Low temperature specific heat curves show single peak structure where the peak-height decreases with J/t. The t-J-U model appears to be of non-Fermi liquid character.