Superconducting condensation energy and neutron resonance in high-T-c superconductors - art. no. 104518

Based on the slave-boson theory of the two-dimensional t-t'-J model, we cal culate the superconducting condensation energy for optimally doped and over doped high-T-c cuprates at finite temperatures using a renormalized random phase approximation. The contributions come from the mean-field part and th e antiferromagnetic spin fluctuations. In the presence of neutron resonance peak at (pi,pi), the latter is shown to have similar temperature and dopin g dependences as the difference in antiferromagnetic (AF) exchange energy b etween the normal and the superconducting state. This difference has been p roposed to be related to the superconducting condensation energy by Scalapi no and White. The total condensation energy, however, is about 1/2 smaller than the proposed AF exchange energy difference and shows a more rapid decr ease as the temperature rises. The doping dependence of the condensation en ergy is found to be consistent with experiments. In particular, near zero t emperature, our result shows a good quantitative agreement with experiments .