title: Random tiling and topological defects in a two-dimensional molecular network.
abstract: A molecular network that exhibits critical correlations in the spatial order that is characteristic of a random, entropically stabilized, rhombus tiling is described. Specifically, we report a random tiling formed in a two-dimensional molecular network of p-terphenyl-3,5,3',5'-tetracarboxylic acid adsorbed on graphite. The network is stabilized by hexagonal junctions of three, four, five, or six molecules and may be mapped onto a rhombus tiling in which an ordered array of vertices is embedded within a nonperiodic framework with spatial fluctuations in a local order characteristic of an entropically stabilized phase. We identified a topological defect that can propagate through the network, giving rise to a local reordering of molecular tiles and thus to transitions between quasi-degenerate local minima of a complex energy landscape. We draw parallels between the molecular tiling and dynamically arrested systems, such as glasses.
authors.affiliation: School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: Matthew O
authors.initials: MO
authors.lastname: Blunt
authors.forename: James C
authors.initials: JC
authors.lastname: Russell
authors.forename: María Del Carmen
authors.initials: Mdel C
authors.lastname: Giménez-López
authors.forename: Juan P
authors.initials: JP
authors.lastname: Garrahan
authors.forename: Xiang
authors.initials: X
authors.lastname: Lin
authors.forename: Martin
authors.initials: M
authors.lastname: Schröder
authors.forename: Neil R
authors.initials: NR
authors.lastname: Champness
authors.forename: Peter H
authors.initials: PH
authors.lastname: Beton