EXCITATION-SPECTRA OF AN EFFECTIVE D-WAVE MODEL FOR CUPRATE SUPERCONDUCTIVITY

An exact-diagonalization technique on finite-size clusters is used to study the ground states and some excitation spectra of the two-dimensi onal effective Fermi-liquid model derived from numerical studies of th e t-J model. We show that there is actually a reasonable range of para meter values where the d-wave pairing of holes occurs and the low-lyin g excitation can be described by the picture of Bogoliubov quasipartic les in the BCS pairing theory but that the clustering of holes rather easily occurs for some stronger attractions.