Pairing of Fermious Coupled with Spin-1/2 Heisenberg System : Exact Diagonalization Study for Mechanism of High-T_c Superconductivity

概要

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A coupled spin-fermion system is investigated as a model of high-7'. supercondutivity. By the exact diagonalization technique, the binding energy of two fermioxand several correlation functions in the ground state are calculated to study possibpairings of holes in orbitals of p., p., d..x ,2 etc. The bound states of fermions are sugested in two regions in the parameter space. In the small transfer region, it is causeby local defects induced in the antiferromagnet at the fermion sites. The 1arg?transfer region is characterized by the relatively extended disturbance of the antiferomagnetic correlation of the substrate spins, where the fermion forms singlet-Nilcloud around it. The latter is a characteristic feature of the antiferromagnetic fernion-spin coupling. The relevance of the latter region to high-7'. superconductivitydiscussed. The possibilities of bound states of fermions in Kondo lattices are also i?vestigated.
社団法人日本物理学会の論文
1989-04-15