A versatile fabrication method for cluster superlattices

TL;DR

This paper introduces a versatile method for fabricating highly perfect cluster superlattices on graphene/Ir(111), applicable to various materials, and investigates their stability, binding sites, and growth criteria.

Contribution

It presents a new fabrication approach enabling the growth of diverse cluster superlattices, including materials previously difficult to form such structures.

Findings

Successful growth of Ir, Pt, W, Re superlattices on graphene/Ir(111)

Low temperature deposition and seeding enable superlattice formation for challenging materials

Superlattices exhibit temperature stability and well-defined binding sites

Abstract

On the graphene moire on Ir(111) a variety of highly perfect cluster superlattices can be grown as shown is for Ir, Pt, W, and Re. Even materials that do not form cluster superlattices upon room temperature deposition may be grown into such by low temperature deposition or the application of cluster seeding through Ir as shown for Au, AuIr, FeIr. Criteria for the suitability of a material to form a superlattice are given and largely confirmed. It is proven that at least Pt and Ir even form epitaxial cluster superlattices. The temperature stability of the cluster superlattices is investigated and understood on the basis of positional fluctuations of the clusters around their sites of minimum potential energy. The binding sites of Ir, Pt, W and Re cluster superlattices are determined and the ability to cover samples macroscopically with a variety of superlattices is demonstrated.