INTERPLAY OF DISORDER AND NONLINEARITY ON CARRIER GROUND-STATE

The effects of disorder on the polaron ground state are investigated both analytically and numerically. The time evolution of a carrier injected in a 1D deformable and disordered lattice where the phonons are damped shows that the ground state is a long-lived localized polaron. By combining statistical and scaling analysis, we show that the extent of the wave function is given by a function λ-1f(2/3/λ), where measures the disorder and λ the nonlinearity. From this result, it was possible to conjecture that the ground state is always localized in 2D or 3D nonlinear disordered systems. © 1995 The American Physical Society.