title: Structural and configurational properties of nanoconfined monolayer ice from first principles.
abstract: Understanding the structural tendencies of nanoconfined water is of great interest for nanoscience and biology, where nano/micro-sized objects may be separated by very few layers of water. Here we investigate the properties of ice confined to a quasi-2D monolayer by a featureless, chemically neutral potential, in order to characterize its intrinsic behaviour. We use density-functional theory simulations with a non-local van der Waals density functional. An ab initio random structure search reveals all the energetically competitive monolayer configurations to belong to only two of the previously-identified families, characterized by a square or honeycomb hydrogen-bonding network, respectively. We discuss the modified ice rules needed for each network, and propose a simple point dipole 2D lattice model that successfully explains the energetics of the square configurations. All identified stable phases for both networks are found to be non-polar (but with a topologically non-trivial texture for the square) and, hence, non-ferroelectric, in contrast to previous predictions from a five-site empirical force-field model. Our results are in good agreement with very recently reported experimental observations.
authors.affiliation: CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain.|Department of Materials and the Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Fabiano
authors.initials: F
authors.lastname: Corsetti
authors.affiliation: CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain.
authors.forename: Paul
authors.initials: P
authors.lastname: Matthews
authors.affiliation: CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain.|Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom.|Basque Foundation for Science Ikerbasque, 48011 Bilbao, Spain.|Donostia International Physics Center, 20018 Donostia-San Sebastián, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Artacho