CHARGE-DENSITY-WAVE TRANSITION AND INSTABILITY IN INTERCHAIN COUPLED ORGANIC FERROMAGNETS WITH NEXT-NEAREST-NEIGHBOR HOPPING INTERACTION

Considering interchain interaction and the intrachain next-nearest-nei ghbor hopping interaction, within the self-consistent-held Hartree-Foc k approximation, we deal with two neighboring organic ferromagnetic ch ains. We take into account the pi-electrons, the Hubbard repulsion, an d antiferromagnetic correlation between pi-electrons and side radical electrons. It is shown that there appear to be two kinds of charge den sity waves successively when the next-nearest-neighbor hopping interac tion is greater than a critical value, which decreases with the interc hain coupling. The first charge density wave is accompanied by a bond order wave and the second one has no lattice distortion. The spin dens ity wave along the main chain is modulated by the charge density wave. It is also found that the interchain coupling and the next-nearest-ne ighbor hopping integral destabilizes the ferromagnetic ground states. (C) 1998 American Institute of Physics.