講演題目：　STM vortex core spectroscopy and non conventional pairing in high temperature superconductors

講　師　：　Christophe Renner (University of Geneva)

日　時　：　平成10年11月20日（金）
                    （以前お知らせした11月27日（金）を訂正します）
　　　　　　15:30〜17：00
場　所　：　北海道大学理学部２号館４階409講義室

要　旨　：
The quasiparticle density of states is a key ingredient in the quest for the mechanism of high temperature superconductivity. One of the common features of high- and low-temperature superconductors is a gap in the quasiparticle excitation spectrum at the Fermi level related to the carrier pairing below the superconducting transition temperature ( T c). However, in high temperature superconductors (HTS), its characteristics are very unusual and depart highly from the BCS predictions. One of the striking spectroscopic signatures of HTS is the persistence of a gap in the normal state above T c. Tunneling spectroscopy shows that this normal state gap is intimately related to the superconducting gap. Recently, it was put into a new perspective as it was also found at low temperature inside the vortex cores of Bi2Sr2CaCu2O8 by scanning tunneling spectroscopy. These latest results are consistent with the existence of incoherent pairing states in the normal state above T c and inside the vortex cores below T c. They suggest that these materials are in an intermediate regime between BCS and Bose-Einstein condensation.

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