title: A systematic typology for negative Poisson's ratio materials and the prediction of complete auxeticity in pure silica zeolite JST.
abstract: Single crystals can commonly have negative Poisson's ratio in a few directions; however more generalised auxeticity is rarer. We propose a typology to distinguish auxetic materials. We characterise numerous single crystals and demonstrate that partial auxeticity occurs for around 37%. We find average auxeticity to be limited to α-cristobalite and no example of complete auxeticity. We simulate two hundreds pure silica zeolites with empirical potentials and quantum chemistry methods, and for the first time identify complete auxeticity in a zeolite network, JST.
authors.affiliation: College of Engineering, Mathematics and Physical Science, University of Exeter, EX4 4QF, UK. a.s.h.marmier@exeter.ac.uk.
authors.forename: M
authors.initials: M
authors.lastname: Siddorn
authors.forename: F-X
authors.initials: FX
authors.lastname: Coudert
authors.forename: K E
authors.initials: KE
authors.lastname: Evans
authors.forename: A
authors.initials: A
authors.lastname: Marmier