Interchain coupling and electronic band structure in polydiacetylenes

We present a numerical study on an extensioned Su-Schrieffer-Heeger(SSH) model of the effects on interchain coupling interaction on electronic band structure in polydiacetylene (PDA). The results show that the degeneracy of energy levels with respect to different chains is lifted and the energy levels split off due to interchain coupling. the location of energy bands shifts symmetrically and the shape of energy bands changes, especially for the lowest conduction band and the highest valence band. As a result, the energy gap becomes narrower and the total bandwidth gets broader.