Dc-Driven Diatomic Frenkel-Kontorova Model

We investigate the resonance steps, spatiotemporal dynamics, and dynamical phase diagrams of the dc-driven diatomic Frenkel-Kontorova model. The complete resonance velocity spectrum is given. The diatomic effects result in each resonant state being characterized by two integer pairs, $(k_1,k_2)$ and $(k_1,k_2^{\prime})$. In the high-velocity region the linear response of the average velocity, $v$, of the chain to the driving force $F$ is often punctuated by subharmonic resonances $(k_1>k_2)$. There are two kinds of nonlinear response regions in the high-velocity region. A new physical interpretation of the mean-field treatment is presented.