Properties of the Ac Driven Frenkel-Kontorova Model with Deformable Substrate Potential
Shapiro steps are studied in the ac driven overdamped Frenkel-Kontorova model with deformable substrate potential. Appearance of very large subharmonic steps due to deformation of the substrate potential significantly influences the stability and existence of harmonic steps. Strong correlation among harmonic and subharmonic steps has been observed in which, the larger the width of half-integer steps, the smaller that of harmonic steps. Deviation from the well-known Bessel-like oscillations of the steps with amplitude have been observed and three different types of behavior classified. Strong influence of the frequency of the ac driving force on the appearance and size of subharmonic steps has been observed.