Analysis of electromechanically induced long-wavelength rippling instability on surfaces of crystalline conductors.

We report a systematic analysis of the surface morphological stability of mechanically stressed electrically conductive crystalline solids that are disturbed from their planar surface state according to long-wavelength shape perturbations under the simultaneous action and in the absence of an applied electric field. The analysis is based on self-consistent dynamical simulations according to a fully nonlinear model of driven surface morphological evolution in conjunction with linear stability theory. We find that for perturbations with a longer-than-critical wavelength a morphological instability is triggered that leads to the formation of a pattern of secondary ripples on the surface morphology. Special emphasis is placed on the effects of the amplitude and the wavelength of the initial perturbation on the surface morphological evolution beyond the onset of the rippling instability. The analysis establishes the relationship between this secondary rippling instability and surface cracking instabilities and provides a detailed characterization of the rippled surface morphologies. The effects of surface diffusional anisotropy on this rippling phenomenon also are examined. We demonstrate that this secondary rippling is a general long-wavelength surface morphological instability phenomenon and is not due to the action of the applied electric field. Furthermore, we show that a sufficiently strong electric field can inhibit both this rippling instability and surface cracking instabilities. [ABSTRACT FROM AUTHOR]