MODULATION OF OSCILLATIONS OF NONLINEAR MODES ON THE CYLINDRICAL SURFACE OF A3B CRYSTAL

Abstract

The work is devoted to the study of the nature of oscillations of nonlinear localized modes near the surface of a crystal with cylindrical symmetry. The topology of the surface has a significant effect on such oscillations. The properties of the oscillatory system were studied based on the position of discrete breathers and quasi-breathers. This allows you to compare characteristics with fluctuations in volume, highlight common features and differences. A model of an A3B crystal with an L12 superstructure and interaction parameters for Pt3Al was considered. The size of the model was 18825 atoms, the radius of the cylinder was about 10 lattice parameters. Interatomic interactions were specified by the EAM potential. The nonlinearity of the bonds is most pronounced near the crystal surface; as a result of insignificant deviations from the equilibrium position, localized modes can be excited. Their properties depend on the position of the excited atoms on the crystal surface. The article considers two such variants of the arrangement of excited atoms. It is shown that the oscillations are of a complex nature. And the modulating component depends on the initial excitation conditions. The frequencies of localized surface modes and modulation frequencies were calculated for a wide range of initial amplitudes. Functional dependencies are selected to describe wave envelopes.