Phase Diagrams and Electromagnetic Propertiesof s-wave Superconductivity of the Extended Hubbard Model with the Attractive Pair-Hopping Interaction

摘要

The characteristics of the extended Hubbard model with the pair-hopping interaction J, i.e. the Penson-Kolb-Hubbard model, are analysed for the case of attractive J (J > 0). The effects of on-site U interaction on the properties of the s-wave superconducting state and mutual stability of the superconducting s-wave and magnetic orderings are examined. The electromagnetic and thermodynamic characteristics of the s-wave superconducting phase for arbitrary particle concentration n and interactions are analysed. The system is evaluated for the case of nearest-neighbours hopping on d-dimensional hypercubic d = 2 (SQ) and d = 3 (SC) nonfrustrated lattices. For SQ lattice the effects of phase fluctuations on the properties of the superconducting state are discussed within the Kosterlitz-Thouless (KT) scenario. The KT critical temperatures T-KT are calculated and compared to the T-c obtained within the BCS-HFA. The Uemura type plots, T-KT vs. lambda(2)(0), are obtained and evaluated as a function of pairing strength and concentration. The results are compared with the case of repulsive J (J < 0) pair-hopping interaction.