STRUCTURE OF KINKS FOR A COMPLEX GROUND-STATE

We propose an approach which allows us to find the structure of elemen tary topologically stable excitations (kinks) for a complex ground sta te (GS) of an atomic chain subjected to the two-dimensional external p otential periodic along the chain and bounded in the transverse direct ion. The approach is based on the consideration of the complex GS cons isting of subchains, each being characterized by the trivial structure , so that the kink of the whole system may be considered constructed o f a set of topological excitations (subkinks) of the subchains.