Nonlinear Excitations in Discrete Model of Conjugated Polymers

抄録

Acoustic component of lattice displacement field is investigated for a soliton and a polaron in Su, Schrieffer and Heeger’s Model for t–(CH)_x, using a perturbation method. Since this component has a small magnitude of the first order with respect to the ratio between the lattice constant and the soliton and/or polaron width, we take account of the higher order corrections to Takayama, Lin-Liu, and Maki’s continuum model. The perturbation calculations determine corrections to electronic wave functions as well as the lattice displacement. Phase shifts of the wave functions are determined to give the correction of the soliton creation energy which turns out to be small. It is not straightforward to proceed to the second order calculations. The difficulty is associated with a new localized state below the valence band. Obtained results are in agreement with numerical simulation works.