## Description:

The objective of the L_Sim laboratory of theory and modeling is to simulate and predict the structure and the properties of nanomaterials. The properties of such materials are governed by their atomic structure. This is the natural scale of the methods developed in the lab combining physics and algorithmics. |
We are working on structures and properties of nano-objects based on semiconductors, metals or insulators. In close collaboration with experimentalists, we compare our predictions of new magnetic properties as well as transport properties of realistic systems. |

## Research topics:

### Diffusion in Si and SiGe

Diffusion phenomena are studied at atomic scale: i) Ab initio calculations are used to identify interstitial and vacancy mechanisms ii) Long distance diffusion is studied by means of Monte Carlo simulation that includes this information.

### Electronic properties of nanostructures

The aim is to model the electronic, optical and transport properties of nanostructures based on semi-conductor materials (wires, quantum dots, ...) or on carbon (tubes, graphene, ...). Tight-binding methods are mainly used, based on a code developed in this lab: TB_Sim.

### Multi-scale approaches for nanostructures

New simulation methods at atomistic level are developed around
wavelets, order N methods and multi-scale approaches
(*ab initio* / Monte Carlo). See also the BigDFT software.

### Nano-exploration

Electron microscopy and diffraction techniques give unique information on the atomic structure at the nano-scale. Yet, it is often necessary to add information coming from modeling and there is a good synergy between these experimental methods and our atomistic simulations.

### Nano-magnetism

We consider magnetic systems in which it is needed to take into account the structure at the atomic level with Heisenberg spin models. A multi-scale method has been developed at the laboratory to model large domains of slow magnetic variations together with atomic and precise descriptions of the system where necessary (Mi_Magnet).