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MM: Fachverband Metall- und Materialphysik

MM 10: Computational Materials Modelling - Accelerated Approaches

MM 10.5: Vortrag

Montag, 20. März 2017, 12:45–13:00, IFW B

Controlling the energy of defects and interfaces in the amplitude expansion of the phase-field crystal model — •Marco Salvalaglio¹, Rainer Backofen¹, Axel Voigt¹, and Ken Elder² — ¹Institute of Scientific Computing, Technische Universität Dresden, 01062 Dresden, Germany — ²Department of Physics, Oakland University, Rochester, 48309 Michigan, USA

The Phase-Field Crystal (PFC) approach describes the dynamics of local atomic probability density on atomic length and diffusive time scales. It generally requires a fine spatial discretization, which limits the application of the method to small systems. The so-called amplitude expansion of the PFC model is known to solve this issue, accounting for the slowly-varying amplitudes of periodic probability densities. However, some restrictions exist in the quantitative description of material properties. In this work, we address the tuning of the interface and defect energy within the amplitude expansion of the PFC model. We extend the standard approach by including an additional energy term accounting for changes in the order of the solid phase. Its effects are investigated by FEM calculations. First, the control of the solid-liquid interface energy is considered as well as the changes induced in the interface morphology. Then, the tuning of the energy of defects is illustrated. The influence of the additional energy term on the dynamics and annihilation of defects is also discussed. We focus here on 2D systems involving crystal lattices with triangular symmetry. The connection of the considered approach to the description of realistic materials is shown for the technology-relevant graphene structure.