This work package will provide an understanding of processes that occur in piezoelectric materials using a range of modelling and visualization techniques. The package employs a multiscale strategy to characterise properties of piezoelectric devices from nano- to macro- scales and includes quantum mechanical, atomistic simulations, finite elements and continues modelling. Quantum mechanical and classical atomistic modelling give insight into processes that happen at the atomic scale (10-10-10-9 m). Various defects such as impurities, vacancies, domain walls, surfaces and interfaces, in general, significantly affect properties of materials. At the nanoscale, defects sometimes have dominating effect on the mechanical, optical, ferroelectric or piezoelectric properties. Therefore, it is important to understand the origin of this phenomenon in order to improve the reliability of existing piezoelectric devices. The results of atomistic modelling, such as defect-perturbed structures and energetics of piezoelectric interfaces, will serve as an input for further studies by finite element and continues modelling techniques. The finite element and continuous modelling techniques will characterise further the properties of piezoelectric materials on a large scale from 10-6 to 10-3 meters. We will develop a state-of-the-art multiscale methodology that provides self-consistent piezo-response of defect-perturbed material at microscale. The continuous modelling will characterise the effects of sample geometry and size on the response of micro- and nano-scaled artefacts that are subjected to deformation caused by mechanical, thermal and electrical stimulation. The models define properties needed in simulations of piezoelectric-based devices and help to design experiments for the measurement of these properties. This package will also develop Digital Image Correlation (DIC) processing technology, a method that visualises changes in images for strain measurements at the nanoscale. The application of this technique allows us to perform the analysis of structural charges in nano-scale piezoelectric materials. The Nanostrain project as a whole aims to do just that- characterising how materials strain at the nanoscale, with a view to driving innovation in next generation electronics devices. This work package is led by NPL, with PTB and BAM acting as partners. CMI is developing the Digital Image Correlation processing technology. For more information on Work Package 4, please contact Anna Kimmel on: a.kimmel@npl.co.uk
