title: Spontaneous formation of high-index planes in gold single domain nanocrystal superlattices.
abstract: Crystals of nanocrystals, also called supracrystals and nanocrystal superlattices, are expected to exhibit specific properties that differ from both the corresponding bulk material and nanosized elementary units. In particular, their surfaces have a great potential as nanoscale interaction plateforms. However, control of the symmetry, compacity, and roughness of their surfaces remains an open question. Here, we describe the spontaneous formation of upper vicinal surfaces for supracrystals of Au nanocrystals grown on a sublayer of ordered Co nanocrystals. Stepped or kinked surfaces vicinal to the {100}, {110}, and {111} planes are observed to be extended on the micrometer range. The formation of such high-index planes is explained by a heteroepitaxial relationship between both Co and Au nanocrystal superlattice.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 8233, MONARIS , F-75005, Paris, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Goubet
authors.forename: Jianhui
authors.initials: J
authors.lastname: Yang
authors.forename: Pierre-Antoine
authors.initials: PA
authors.lastname: Albouy
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Pileni
keywords: Nanoparticle superlattice; gold nanoparticle; heteroepitaxy; high-index plane; nanocrystallinity; vicinal surfaces