Proximity effects near the interface between d-wave superconductors and ferro/antiferromagnets

We study the proximity effects near the interface between a d-wave superconductor (S) and a ferromagnet (F) or an antiferromagnet (AF). The S-side (F and AF-side) is described by the attractive (repulsive) Hubbard model, and the Bogoliubov de Gennes equation derived within the Hartree-Fock approximation is solved numerically. The superconducting order parameter and the magnetization (m) can coexist near the interface, and the spatial variation of m induces the spin-triplet p-wave component in both F and AF cases. The local density of states is also calculated and discussed.Comment: 4 pages, 7 ps figures, to appear in J.Phys.Soc.Jpn. Vol.68, No.1

Phase Separation Induced by Density-Dependent Hopping Terms

We study phase separation in the $t-t'-J$ model in which the constraint of no double occupancy due to strong electron correlations leads to effective narrowing of the band width. Using a mean-field approximation, we calculate the compressibility in the normal state and show that the phase separation can be induced by the variation of the band width.Comment: 6 pages, 3 figure