The superposed electric field effect on the charge transport and polaron formation in molecular crystals

Abstract

We study the polaron formation and its mobility in a onedimensional molecular crystal subjected to superposed static and harmonic electric fields. Such molecular chain exhibits intermolecular vibrational degrees of freedom, which makes the carrier-lattice interaction an important parameter of the system. By exploring field settings in which the preferential transport occurs, we show the existence of different small polaron formations, including those that travel close to the sound velocity or that are stationary by self-trapping. Electric fields magnitudes and carrier-lattice coupling have also been analyzed, which allowed to show a phase diagram that describes the existing regimes. In addition to thresholds between the mobile and stationary polaron regimes, this phase diagram unveils an unusual aspect: a metastable polaron formation.