Modeling of glycine polymorphic and switching properties

Main results of the modeling and computational studies of two the most interesting non-centro-symmetric polymorphic glycine structures: β-glycine (space group P2
₁
) and γ-glycine (space group P3
₂
), are presented in this work. These structures reveal piezoelectric and polar properties. But the value of polarization is not clear as well it's switching behaviour. In this work computational modelling of both glycine polymorphic crystal structures were performed using combined method with Local Density Approximation (LDA) first principle calculations of atomic optimized crystal structures on Linux cluster and with molecular semi-empirical PM3 calculations by HyperChem 8.0 This computational study is corroborated by measured nanoscale data obtained by atomic force and piezo-response force microscopy (AFM / PFM).