At the nanoscale, the structural properties of materials (0D/1D/2D) can be difficult to predict because they involve long-range interactions that cannot be avoided. Many examples are discussed in the literature such as the grafting of molecules on a graphene sheet, inter-plane coupling in 2D heterostructures or in multiwall carbon nanotubes, the adhesion of catalytic nanoparticles, etc. In this context, we wish to implement a multi-scale approach by coupling atomic scale modelling (empirical, semi-empirical or ab initio modelling) with a continuous approach via finite element calculations (FE) to better understand the electronic modifications induced by nano-objects under stress.
The aim of this internship is to apply this methodology to self-assembled silicon nanostructures as a first application. The work will be done in two stages. First of all, it will be necessary to characterize the structural properties of the systems under consideration, thanks to the development of our multi-scale approach involving the transition from an atomistic description to a mechanical framework of continuum media to take into account the FEs of long-range interactions that drive the effects of self-organization. Subsequently, the electronic properties of these systems will be characterized by combining ab initio calculations and a tight-binding model (order-N method) perfectly adapted to handle large systems (104-105 atoms) where long-range elastic effects are dominant.
It should be noted that this research activity will benefit from the joint development of unique skills present in the laboratory in the field of low-dimensional objects and the mechanical behaviour of materials.
Job: Internship (4-6 months)
Academic level : Master degree
Location: LEM, Châtillon
Expertise: Solid state physics, Materials Science. Interest in theoretical physics and numerical simulations (coding, data post-processing).