Holon pair condensation and phase diagram of high-T-c cuprates

A possibility of holon (boson) pair condensation is explored for hole-doped high-T-c cuprates, by using the Li(1) slave-boson representation of the t- J Hamiltonian with the inclusion of hole-hole repulsion. A phase diagram of the hole doped high-T-c cuprates is deduced by allowing both the holon pai ring and spinon pairing channels. It is shown that the spin gap size remain s nearly unchanged below the holon pair condensation temperature. We find t hat the s-wave holon pairing under the condition of d-wave spin singlet pai ring is preferred, thus allowing d-wave hole pairing. [S0163-1829(99)00933- 9].