Unconventional charge density wave in coupled electron-phonon system

We report our study on unconventional charge density waves (UCDW) in pure quasi-one dimensional conductors. We develop a new possible mechanism of establishment of such a low temperature phase, in which the driving force of the phase transition is the electron-phonon interaction With Coupling depending on both the momentum transfer and the momentum of the scattered electron. Mean field treatment is applied to obtain the optical conductivity. The inclusion of collective modes causes significant change with respect to the cluasiparticle contribution, and leads to an effective mass which is nonmonotonic in temperature as opposed to conventional charge density waves.