title: Apparent scarcity of low-density polymorphs of inorganic solids.
abstract: For most inorganic solids, very few dense polymorphs and no low-density polymorphs are observed. Taking a wide range of tetrahedrally-coordinated binary solids (e.g., ZnO, GaN) as a prototypical system, we show that the apparent scarcity of low- density polymorphs is not due to significant structural or energetic limitations. Using databases of periodic networks as sources of novel crystal structures, followed by ab initio energy minimization, we predict a dense spectrum of low-density low-energy polymorphs. The diverse range of materials considered indicates that this is likely to be a general phenomenon.
authors.affiliation: Departament de Química Física and Institut de Química Teòrica i Computacional, Universitat de Barcelona, E-08028 Barcelona, Spain.
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Zwijnenburg
authors.forename: Francesc
authors.initials: F
authors.lastname: Illas
authors.forename: Stefan T
authors.initials: ST
authors.lastname: Bromley