Enhancing DFT-based energy landscape exploration by coupling quantum mechanics and static modes

Unravelling the atomic scale diffusion that can occur at the surface, at the interface or into the bulk is challenging: multi-scale modelling approaches usually require intensive prospective calculations and moreover huge human investment. In this article, the Static Mode (SM) approach is coupled with Quantum Mechanics (QM) calculations in order to guide the exploration of the energy landscape, by optimizing the choice of events that are significant for the evolution of the system. SM enable the determination of the strain field of a set of atoms submitted to external and localized stresses, like atomic displacements. Here, we present a workflow based on the systematic SM exploration, with the objective to reduce both exploration time and human load when used with ab initio level calculations. The QMSM coupling allows the screening, scoring and selection of relevant directions that are further used to initiate and study diffusion in atomic systems. The most relevant deformations are then refined and relaxed with DFT calculations. In this paper, the overall QMSM approach is described and we discuss its use for the identification of atomic diffusion in two different systems of interest: grafting of a molecule on an oxide surface and studying the dynamical behavior of a point-defect in a bulk crystalline material.