Bloch oscillations in a one-dimensional organic lattice

We present a model study on the dynamics of electron transport of a dissociated polaron under a strong uniform electric field in a one-dimensional organic lattice. The simulations are performed within the framework of the Su-Schrieffer-Heeger model coupled by a Newtonian equation of motion with a nonadiabatic evolution method. It is found that the dissociated polaron propagates in the form of a freelike electron and performs spatial Bloch oscillations (BO's). In contrast to normal BO's in a rigid lattice, the mean displacement of the oscillating electron will have a net forward movement in the direction of the electric field, which is dependent on the strong electron-lattice couplings in the organic lattice. It is also found that a transient polaron forms at the end of each period of BO's, accompanying the appearance of discrete polaron levels in the gap of the band. The effects of electron-electron interactions and bond disorder in the organic lattice are briefly discussed.