Evolution of Non-Equilibrium Profile in Adsorbate Layer under Compressive Strain

TL;DR

This paper studies how the surface profile of a strained adsorbate layer evolves over time under different conditions, revealing rapid changes driven by domain wall dynamics, with implications for understanding surface phase transitions.

Contribution

It introduces a detailed simulation study of non-equilibrium profile evolution in strained adsorbates, highlighting the role of domain walls in the dynamics near phase transitions.

Findings

Profile evolution rate depends on mismatch, coverage, and substrate potential.

Fast time evolution linked to domain wall creation and diffusion.

Results are consistent with experimental observations in Pb/Si(111) systems.

Abstract

We investigate the time evolution of an initial step profile separating a bare substrate region from the rest of the compressively strained adsorbate layer near a commensurate to incommensurate transition. The rate of profile evolution as a function of the mismatch, coverage and the strength of the substrate potential are determined by Brownian molecular dynamics simulations. We find that the results are qualitatively similar to those observed for the Pb/Si(111) system. The anomalously fast time evolution and sharpness of the non-equilibrium profile can be understood through the domain wall creation at the boundary and its subsequent diffusion into the interior of the adsorbate layer.