講演題目：　Phase Diagram and Hole Pairing of High Tc Superconductors Based on Extended　t-J Hamiltonian
　
講　師　：　Prof.Sung-Ho Salk
　　　　　 (Pohang University)

日　時　：　平成11年2月10日（水）　15:30 〜 17:00
場　所　：　北海道大学理学部２号館大学院講義室（2-2-11）

要　旨　：
A variety of experimentally observed phase diagrams of high Tc cuprates are briefly reviewed with emphasis on pseudogap phase. Based on the experimental results, we focus our attention to both the spin gap phase and the d-wave superconducting phase for hole doped high Tc cuprates. By introducing an extended t-J Hamiltonian with a hole-hole interaction term and its slave-boson representaion, we derive a computed phase diagram and discuss the pseudogap phase including the superconducting phase of holon pair condensation. Further both the U(1) and SU(2) slave boson theory of Lee and coworkers will be compared with our results of holon pair condensation. It is shown that the spin gap size remains nearly unchanged below the holon pair condensation temperature. We find that the s-wave holon pairing under the condition of d-wave singlet pairing is preferred, thus allowing the formation of d-wave hole pair.

世話人　 小田　研（011-706-3575、moda@sci.hokudai.ac.jp）
北海道大学・大学院理学研究科・物理学専攻