arXiv subjects

Matthias Gramzow

Publications and source records attributed to Matthias Gramzow.

3 recordsLinked to original sources

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↗

arXiv2011

On the stability of "non-magic" endohedrally doped Si clusters: A first-principles sampling study of MSi16^+ (M =Ti,V,Cr)

Density-functional theory is used to study the geometric and electronic structure of cationic Si16^+ clusters with a Ti, V or Cr dopant atom. Through unbiased global geometry optimization based on the basin-hopping approach we confirm that a Frank- Kasper polyhedron with the metal atom at the center represents the ground-state isomer for all three systems. The endohedral cage geometry is thus stabilized even though only VSi16^+ achieves electronic shell closure within the prevalent spherical potential model. Our analysis of the electronic structure traces this diminished role of shell closure for the stabilization back to the adaptive capability of the metal- Si bonding, which is more the result of a complex hybridization than the orginally proposed mere formal charge transfer. The resulting flexibility of the metal-Si bond can help to stabilize also "non-magic" cage-dopant combinations, which suggests that a wider range of materials may eventually be cast into this useful geometry for cluster-assembled materials.

cond-mat.mtrl-sci↗

arXiv2010

Structural Metastability of Endohedral Silicon Fullerenes

Endohedrally doped Si20 fullerenes appear as appealing building blocks for nanoscale materials. We investigate their structural stability with an unbiased and systematic global geometry optimization method within density-functional theory. For a wide range of metal doping atoms, it was sufficient to explore the Born Oppenheimer surface for only a moderate number of local minima to find structures that clearly differ from the initial endohedral cages, but are considerably more favorable in terms of energy. Previously proposed structures are thus all metastable.

cond-mat.mes-hall↗