Marcel Hülsberg | Searcharxiv

arXiv2026

Roadmap on Advancements of the FHI-aims Software Package

Electronic-structure theory is the foundation of the description of materials including multiscale modeling of their properties and functions. Obviously, without sufficient accuracy at the base, reliable predictions are unlikely at any level that follows. The software package FHI-aims has proven to be a game changer for accurate free-energy calculations because of its scalability, numerical precision, and its efficient handling of density functional theory (DFT) with hybrid functionals and van der Waals interactions. It treats molecules, clusters, and extended systems (solids and liquids) on an equal footing. Besides DFT, FHI-aims also includes quantum-chemistry methods, descriptions for excited states and vibrations, and calculations of various types of transport. Recent advancements address the integration of FHI-aims into an increasing number of workflows and various artificial intelligence (AI) methods. This Roadmap describes the state-of-the-art of FHI-aims and advancements that are currently ongoing or planned.

cond-mat.mtrl-sci↗

arXiv2022

Depinning dynamics of confined colloidal dispersions under oscillatory shear

Strongly confined colloidal dispersions under shear can exhibit a variety of dynamical phenomena, including depinning transitions and complex structural changes. Here, we investigate the behaviour of such systems under pure oscillatory shearing with shear rate $\dotγ(t) = \dotγ_0 \cos(ωt)$, as it is a common scenario in rheological experiments. The colloids' depinning behaviour is assessed from a particle level based on trajectories, obtained from overdamped Brownian Dynamics simulations. The numerical approach is complemented by an analytic one based on an effective single-particle model in the limits of weak and strong driving. Investigating a broad spectrum of shear rate amplitudes $\dotγ_0$ and frequencies $ω$, we observe complete pinning as well as temporary depinning behaviour. We discover that temporary depinning occurs for shear rate amplitudes above a frequency-dependent critical amplitude $\dotγ_0^\mathrm{crit}(ω)$, for which we attain an approximate functional expression. For a range of frequencies, approaching $\dotγ_0^\mathrm{crit}(ω)$ is accompanied by a strongly increasing settling time. Above $\dotγ_0^\mathrm{crit}(ω)$, we further observe a variety of dynamical structures, whose stability exhibits an intriguing ($\dotγ_0, ω$) dependence. This might enable new perspectives for potential control schemes.

cond-mat.soft↗