Stability and Dynamic of strain mediated Adatom Superlattices on Cu<111>

TL;DR

This paper models the stability and dynamics of strain-mediated adatom superlattices on Cu<111> surfaces, combining calculations and Monte Carlo simulations to analyze their formation, stability, and collective diffusion modes.

Contribution

It introduces a comprehensive approach combining substrate strain effects and Monte Carlo simulations to study adatom superlattices on Cu<111> surfaces, including stability conditions and dynamic behavior.

Findings

Hexagonal adatom superlattice observed up to 0.045 ML coverage

Conditions for superlattice stability against nucleation identified

Proposed collective diffusion modes analogous to bulk lattice dynamics

Abstract

Substrate strain mediated adatom density distributions have been calculated for Cu<111> surfaces. Complemented by Monte Carlo calculations a hexagonal close packaged adatom superlattice in a coverage range up to 0.045 ML is derived. Conditions for the stability of the superlattice against nucleation and degradation are analyzed using simple neighborhood models. Such models are also used to investigate the dynamic of adatoms within their superlattice neighborhood. Collective modes of adatom diffusion are proposed from the analogy with bulk lattice dynamics and methods for measurement are suggested. The explanation of surface state mediated interactions for superstructures found in scanning tunnelling microscopy experiments is put in question.