PHASE DIAGRAMS OF TWO FKD MODELS WITH DIFFERENT TRIPLE-WELL INTERACTIONS

Abstract

We introduce two typical Frenkel–Kontorova–Devonshire (FKD) models where the interactions are of different triple-well potentials and the external potentials are of the same parabolic type. The exact phase diagrams are worked out by the use of the effective potential method with the numerical implementation. We also analyze the periodicity of the phase diagrams and find that the properties of the phase structures are closely related to the period of the external potential D.