Electronic Control of Spin Alignment in pi-Conjugated Molecular Magnets
arXiv:cond-mat/0304431 · doi:10.1103/PhysRevLett.90.207203
Abstract
Intramolecular spin alignment in pi-conjugated molecules is studied theoretically in a model of a Peierls-Hubbard chain coupled with two localized spins. By means of the exact diagonalization technique, we demonstrate that a spin singlet (S=0) to quartet (S=3/2) transition can be induced by electronic doping, depending on the chain length, the positions of the localized spins, and the sign of the electron-spin coupling. The calculated results provides a theoretical basis for understanding the mechanism of spin alignment recently observed in a diradical donor molecule.
4 pages, 4 figures, Physical Review Letters (in press)