QUASI-SOLITON STATES IN A 2-DIMENSIONAL DISCRETE MODEL

We present a numerical study of a two-dimensional discrete model for t he interaction between an excitation and the phonons in the adiabatic limit. The static stable configuration has been found by a steepest-de scent algorithm while the equations of motion have been integrated by the Runge-Kutta method. The ground-state configuration shows a self-tr apping transition for a critical value of the coupling constant, while the time evolution from an initial localized excitation has solitonli ke features in a certain range of the parameters. The dynamical simula tion results have strong similarities to the ones obtained in the fram ework of the one-dimensional Davydov model. An extensive threshold stu dy for the soliton generation is also reported. The possible physical implications of our work are discussed especially in connection to the charge transport in the cuprate superconductors.