PROPERTIES OF IR-ACTIVE LATTICE-VIBRATIONS IN THE VICINITY OF KINKS IN THE FRENKEL-KONTOROVA MODEL

The properties of infrared lattice vibrations in the presence of kinks in the Frenkel-Kontorova model are analyzed. Our results show that th e vibration of particles involved in kink formation is very similar to that in a gap mode around a force-constant defect. We found that the IR phonon mode intensity possesses a universal dependence on a certain combination of system parameters and kink concentration. On the basis of these results a criterion is proposed for separating the regime of weakly interacting kinks in the system from the regime of a kink latt ice. (C) 1997 American Institute of Physics.