Normal Dynamics: solving Newton's equations of motion in the reciprocal space

Abstract:
I will present the Normal Dynamics (ND) technique and its implementation into the open source PINDOL code[1]. ND provides a way to integrate the Newton's equations of motion expressed in terms of normal modes by sampling the reciprocal space. First, I will introduce the main idea behind ND, and then I will discuss the sampling strategy and show how it is capable to produce dynamical trajectories at the ab initio level on an ordinary desktop computer. The reciprocal space sampling allows to: i) obtain a systematic improvement of the results accuracy and a fine control of the computational load, ii) account for distortions realized across large atomic distances without the use of large unit cells. I will present three case studies: the first two are aimed to show the capabilities of the ND method, while the latter is about the characterization of Raman spectra at different temperatures in MoS2/MX2 transition metal dichalcogenide heterostructures. Finally, I will discuss how the sampling procedure is general and can be used to simulate periodic, semiperiodic and finite systems such as crystals, slabs, nanoclusters or molecules.