A force‐field based analysis of the deformation mechanism in α‐cristobalite. Issue 7 (19th June 2015)

• Record Type: Journal Article
• Authors: Gatt, Ruben; Mizzi, Luke; Azzopardi, Keith M.; Grima, Joseph N.
• Is Part Of: Physica status solidi. Volume 252:Issue 7(2015:Jul.)
• Page Start: 1479
• Page End: 1485
• Publication Date: 2015-06-19
• Subjects: Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.201552133
• Languages: English
• ISSNs: 0370-1972

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="pssb201552133-sec-0001" sec-type="section"> <p>α‐cristobalite is a metastable polymorph of silica which has the remarkable property of exhibiting a negative Poisson's ratio (auxetic). In this study, the mechanical properties and deformation mechanisms of this system were investigated through a force‐field based approach. Besides simulations on the actual structure of α‐cristobalite, a number of simulations where the rigidity of SiO₂ tetrahedra was increased, were also conducted. This was done in order to obtain a clearer picture of the role which these tetrahedra play in determining the mechanical properties of this system. These systems were loaded in an off‐axis direction in a number of planes about the [001] direction and the deformations observed were compared with those of type II rotating rectangle systems. It was discovered that the mechanical properties of α‐cristobalite can be accurately described through the semi‐rigid version of this model, even for cases where the tetrahedra were fully rigid.</p> </sec> </abstract>