抄録
The dynamics of a charged soliton pinned by an impurity in the presence of an electric field is numerically studied by using Su-Schrieffer-Heeger’s model for trans-polyacetylene. The field is introduced in terms of a time-dependent vector potential which is included in the Hamiltonian in the form of a phase of the transfer integral. The time-dependent Schrödinger equation for the electronic wave functions and the equation of motion for the lattice displacements are numerically integrated in a self-consistent way. When the field is lower than a certain threshold value, the soliton remains trapped and oscillates periodically around the impurity position. As the field is increased, the time period of the oscillation becomes longer. When the field exceeds the threshold value, the soliton is depinned and begins to move in one direction. The threshold field is estimated to be 105–106 V/cm, which is in rough agreement with the value obtained in experiments on polyacetylene lightly doped with AsF5.
