Regensburg 2025 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 15: Crystal Structure Defects / Real Structure / Microstructure
KFM 15.4: Talk
Thursday, March 20, 2025, 10:30–10:45, H9
Simulated nano-extrusion of graphene hyperbolic pseudosphere surfaces — •Peter Klaver1, Alfredo Iorio2, Ruggero Gabbrielli3, and Dominik Legut1 — 1VSB Technical University of Ostrava, Ostrava, Czech Republic — 2Charles University, Prague, Czech Republic — 3Independent researcher
We produce curved graphene hyperbolic pseudosphere surfaces in molecular dynamics (MD) simulation of a nano-scale extrusion process. During the extrusion process the carbon atoms form pentagons, hexagons and heptagons and such a mixture is unrealistically less stable than pure graphite or diamond. During relaxation and lengthy high temperature annealing after the extrusion process, polycrystalline curved graphene with a limited number of point defects is formed. The point defects cause bending of the graphene and the pseudosphere edges even more. When these free edges are removed from the simulations by attaching periodic flat graphene sheets to the pseudosphere edges, the carbon atoms assume positions with a root mean square deviation of some tenths of Å from the mathematical hyperbolic pseudosphere surface. The hyperbolic pseudospheres proved to be mechanically stable against large shearing and elongation deformations as well as against annealing at 1500 K. Our methodology is easy to use, employing the REBO2 carbon interaction potential within the open source MD code LAMMPS. Our method offers a practical way to create simulated stable, curved graphene surfaces with a wide variety of desired shapes. It allows for the testing in advance of the stability of graphene shapes that are to be produced experimentally.
Keywords: graphene; curvature; anneling; molecular dynamics