Atomistic mechanisms for the ordered growth of Co nano-dots on Au(788): comparison of VT-STM experiments and multi-scaled calculations

TL;DR

This study combines VT-STM experiments and multi-scaled simulations to elucidate the atomistic mechanisms behind the ordered growth of Co nanodots on Au(788), revealing stable nanostructure formation over a wide temperature range.

Contribution

It introduces a comprehensive multi-scaled approach integrating experimental and computational methods to understand Co nanodot nucleation and growth on Au(788).

Findings

Stable rectangular Co nanodot array observed from 60 K to 300 K.

Atomistic mechanisms for ordered nucleation identified.

Activation energies for atomic motion quantified.

Abstract

Hetero-epitaxial growth on a strain-relief vicinal patterned substrate has revealed unprecedented 2D long range ordered growth of uniform cobalt nanostructures. The morphology of a Co sub-monolayer deposit on a Au(111) reconstructed vicinal surface is analyzed by Variable Temperature Scanning Tunneling Microscopy (VT-STM) experiments. A rectangular array of nano-dots (3.8 nm x 7.2 nm) is found for a particularly large deposit temperature range lying from 60 K to 300 K. Although the nanodot lattice is stable at room temperature, this paper focus on the early stage of ordered nucleation and growth at temperatures between 35 K and 480 K. The atomistic mechanisms leading to the nanodots array are elucidated by comparing statistical analysis of VT-STM images with multi-scaled numerical calculations combining both Molecular Dynamics for the quantitative determination of the activation energies for the atomic motion and the Kinetic Monte Carlo method for the simulations of the mesoscopic time and scale evolution of the Co submonolayer.