Spin exchange and superconductivity in a t-J-V model for two-dimensional

ANDRÉS GRECO,1 JAIME MERINO,2 ADRIANA FOUSSATS,3 AND ROSS H. MCKENZIE4

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

Año: 2005 vol. 71 p. 1445021 - 1445027

0163-1829

The effect of antiferromagnetic spin fluctuations on two-dimensional quarter-filled systems is studied theoretically.An effective t-J-V model on a square lattice which accounts for checkerboard charge fluctuations andnext-nearest-neighbor antiferromagnetic spin fluctuations is considered. From calculations based on large-Ntheory on this model it is found that the exchange interaction J increases the attraction between electrons inthe dxy channel only, so that both charge and spin fluctuations work cooperatively to produce dxy pairing.