Gap solitons, resonant kinks, and intrinsic localized modes in parametrically excited diatomic lattices

The dynamics of localized nonlinear excitations of resonant frequencies omega(j) (j = 0, 1, 2, 3) and carrier wave frequency omega(e) approximate to omega(j) in a damping and parametrically driven lattice system is considered. The excitations are created in a one-dimensional nonlinearly coupled diatomic pendulum lattice which is subjected to a vertical oscillation of frequency 2 omega(e). The recent experimental observation of gap solitons, resonant kinks, and intrinsic localized modes in the diatomic pendulum lattice system are explained by using an extended nonlinear Schrodinger theory after neglecting the nonuniformity of the pendulums and the small periodic modulations of the amplitudes of the excitations.