RQMP Research Seminar

Understanding the link between the structure of the energy surface at the atomic level and the kinetic properties of complex materials at the macroscopic level

Normand Mousseau

Département de Physique
Université de Montréal

The evolution of atoms in a material can be seen as a walk on an energy surface which describes the physics of the system. This image is often used, a posteriori, to explain or justify kinetic phenomena. However, we are only beginning to map the energy surface of complex materials, as effective theoretical and numerical approaches are being developed. In recent years, using various exploration methods, such as the activation and relaxation technique (ART nouveau) — a very efficient open-ended transition-point search method— and kinetic ART — an off-lattice kinetic Monte Carlo algorithm with on-the-fly catalog building, we have attempted to conduct exhaustive sampling in various systems, ranging from crystalline metals with amorphous semiconductors. The results of these studies allow us to better understand the diversity of diffusion mechanisms and, more recently, the correlations between the diffusion barrier and the prefactor, a correlation called “compensation law” or “Meyer-Neldel law”. In this presentation, I will present an overview of the methods to then focus on these fascinating results.