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Elastic and piezoelectric properties of nanowires: from atoms to continuum,from chemistry to mechanics

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HAL Id: hal-01081755

https://hal-upec-upem.archives-ouvertes.fr/hal-01081755

Submitted on 10 Nov 2014

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Elastic and piezoelectric properties of nanowires: from atoms to continuum,from chemistry to mechanics

Gilberte Chambaud, Alexander Mitrushchenkov, Julien Yvonnet

To cite this version:

Gilberte Chambaud, Alexander Mitrushchenkov, Julien Yvonnet. Elastic and piezoelectric properties of nanowires: from atoms to continuum,from chemistry to mechanics. Recent advances in Material Science” CCS-SCF meeting, Oct 2013, Paris, France. �hal-01081755�

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Elastic and piezoelectric properties of nanowires: from atoms to continuum,from chemistry to mechanics

Gilberte Chambaud

Laboratoire Modélisation, Simulation Multi-Echelle, MSME UMR 8208 CNRS - Université Paris-Est Marne la Vallée,

5 bd Descartes, 77454 Marne-la-Vallée, France

Abstract

Experimentally, mechanical and piezoelectrical properties of individual nanowires have been extensively explored. However, predicting properties of structures or composites based on electromechanic nanowires is highly challenging and remains an open problem for the following reasons: (a) the multiscale nature of the problem: the response of the composite is macroscopic, while the structure is defined at the nanoscale level, and the properties of the constituents, as well as the interactions (interfaces mechanics) between the constituents must be predicted at the atomic scale. Furthermore, determining the different coefficients associated with the properties at the nano/atomic level requires ab initio quantum mechanics calculations; (b) electromechanical models for continuum mechanics describing surface effects due to the nanoscale have not been proposed so far; (c) the computational costs can be out of scope if we do not introduce appropriate couplings between scales and models to take maximum advantage of each model in its range of validity. Thus, multiscale modelling strategies as well as novel numerical methods seem the only way to fully describe electromechanical nanowire-based composites.

Starting from fully atomistic calculations, we have developed a classical, continuous

mechanics, model of wurtzite nanowires, using FEM discretization. Ab initio calculations of AlN

and ZnO wurtzite [0001] nanowires have been performed with diameters up to 4 nm. It is shown

that the nanowires can be well represented by an internal part with AlN bulk elastic properties,

and one-atomic surface layer with its own elastic behaviour. To deal with more

nanostructures/nanoparticles complex geometries, a finite element method using surface

elements with their own elastic properties is developed. The surface elastic coefficients are

provided by ab initio calculations through a slab procedure. The finite element model is

compared with the full ab initio nanowires calculations and a good agreement is demonstrated.

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