Solid State Communications
The direct and indirect correlation between organic radicals in a quasi-one-dimensional organic ferromagnet model is investigated. By introducing random-phase-approximation (RPA), the typical spin-wave excitation modes of the model are obtained. The stiffness of acoustic spin-wave mode is found to represent the correlation between radicals. The variation of the stiffness according to the parameters of the system is discussed and indicates the unique features of the organic ferromagnet. Copyright (C) 1996 Elsevier Science Ltd
关键词:
hubbard-model
Journal of Physics-Condensed Matter
We deal with two neighbouring pi-conjugated organic ferromagnetic chains with a Hamiltonian including the Hubbard on-site electron-electron repulsion and nearest-neighbouring Coulomb repulsion. We take into account the interchain coupling as an interchain electron-transfer term, which is different with respect to different sites in chains. The distribution of charge density, the ferromagnetic order and the stability of the high-spin ground state are studied in detail. It is shown that the nearest-neighbouring Coulomb repulsion leads to inhomogeneous distribution of charge density and spin density with respect to different sites. The interchain coupling results in transfers of charge density and spin density between the main chain and the side radicals. The interchain coupling stabilizes the high-spin ground state while the nearest-neighbouring Coulomb repulsion makes it unstable.
关键词:
hubbard-model
