Theory of one-dimensional solitons, polarons, and multipolarons: An alternative formulation

We develop an alternative formulation of the theory of solitons, polarons, and multipolarons in quasi-one-dimensional degenerate and nondegenerate conducting polymers, starting from the continuum Hamiltonian introduced by Brazovskii and Kirova. Based on a convenient real-space representation of the electron Green function in one dimension, we present a simple method of calculating the Green function and the density of states in the presence of a single soliton or polaron defect, through which we derive exact expressions for the soliton, polaron, and multipolaron excitation energies and the self-consistent gap functions for an arbitrary value of the electron-phonon coupling constant. We apply our results to (Formula presented)-polyacetylene.