EFFECTIVE KINK-KINK INTERACTION IN A ONE-DIMENSIONAL MODEL MEDIATED BY PHONON EXCHANGE

The general 1D double well model with anharmonic interaction is consid ered in the displacive limit. Expansion of the Hamiltonian around a mu ltikink state results in a phonon-kink Hamiltonian. It is shown that a t rather low temperatures and short wavelengths the phonon-kink intera ction can be treated in Born approximation, leading to a decomposition of the multikink-phonon Hamiltonian. Elimination of the phonons resul ts in an effective potential for the kink-kink interaction, which corr esponds to the one-dimensional analog of the RKKY interaction. This lo ng-range interaction is inherent only for models with anharmonic on-si te potentials and not in case of a double-parabola model.