ELECTRON-PHONON AND EXCHANGE INTERACTIONS IN THE ONE-DIMENSIONAL PI-DELECTRON-SYSTEMS

A new model Hamiltonian is proposed for the suggestion of new one-dime nsional (1D) pi-d electron systems. The effects of the pi-electron pho non interaction lambda and the antiferromagnetic exchange interaction between nearest-neighbor pi and d electrons, j(K), on the electronic s tates of these systems have been investigated. The case of a half-fill ed band has been studied by using a mean-field approximation and perio dic boundary conditions. As the value of lambda (j(K)) is increased, t he spin density and the energy gap of the pi electron decrease (increa se), while the dimerization increases (are almost constant). It turns out that the electron-phonon and exchange interactions are very import ant for the control of the electronic properties of the 1D pi-d electr on systems.