EFFECTS OF INTERCHAIN COUPLINGS ON EXCITATIONS IN FINITE-LENGTH CONDUCTING POLYMER-CHAINS

In the framework of the tight-binding model, the effects of longitudin al as well as transverse coupling between polyacetylene chains with di fferent lengths and the electron-electron interactions on excitations have been studied. A new spinless charged polaronic excitation (q = +/ -e, s = 0) was obtained due to the transverse interchain coupling, whi ch is different from the general magnetic polaron (q = +/-e, s = 1/2) obtained in the perfect one-dimensional model. Due to its end position ing, a polaron is more easily stimulated energetically in a longer cha in than in a shorter one, and it can hop to the longer chains nearby v ia either transverse or longitudinal interchain coupling. In addition, the transverse coupling decreases the energy of creation of a polaron . Considering the strong electron-electron interactions and the end po sitioning of chains in actual materials, we concluded that the one-dim ensional model of conducting polymers is fairly appropriate in certain circumstances.