Step meandering during epitaxial growth

The present study is a theoretical investigation of meandering steps on vicinal surfaces, an instability phenomenon occurring during epitaxial growth in crystals. Results are based on the linear stability analysis using a thermodynamically consistent multiphysics continuum mechanics model, which accounts for the dynamics of adatom diffusion on terraces (the dynamical effect) and attachment-detachment at steps and generalizes the expression of the step chemical potential by incorporating the necessary coupling between the diffusion fields on adjacent terraces (the chemical effect). Having previously shown that these dynamical and chemical effects can explain the onset of straight-step bunching without recourse to the inverse Ehrlich-Schwoebel (iES) barrier or other extraneous mechanisms, the novelty of the present work consists in the extension of our previous 1D analysis for straight steps to a 2D modeling for the meandering steps. Like in the straight-step context, the chemical and dynamical effects have a non-negligible influence on the stability of the system, leading to non-trivial results like multimode instabilities or abrupt bunching-to-meandering transitions.