We investigate the dynamics of a compressively strained adsorbed layer on a periodic substrate via a simple two-dimensional model that admits striped and hexagonal incommensurate phases. We show that the mass transport is superfast near the striped-hexagonal phase boundary and in the hexagonal phase. For an initial step profile separating a bare substrate region (or “hole”) from the rest of a striped incommensurate phase, the superfast domain wall dynamics leads to a bifurcation of the initial step profile into two interfaces or profiles propagating in opposite directions with a hexagonal phase in between. This yields a theoretical understanding of the recent experiments for the Pb/Si(111) system.
- adsorbate layers
Granato, E., Ying, S. C., Elder, K., & Ala-Nissilä, T. (2013). Anomalous fast dynamics of adsorbate overlayers near an incommensurate structural transition. Physical Review Letters, 111(12), 1-5. . https://doi.org/10.1103/PhysRevLett.111.126102