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Proposing Institution

Computational Chemistry, Universität Erlangen
Project Manager

Florian Wullschläger
Nägelsbachstr. 25
91052 Erlangen
Dislocation, i.e. one-dimensional line defects, are the main carriersof plastic deformation in crystalline solids. In a recent TEM studyit was shown that dislocations even exist in materials as thin astwo graphene layers [1]. Using atomistic simulations based on the registry-dependent potential of Kolmogorov and Crespi [2] we haveshown that the properties of dislocations in quasi-2D crystals differsignificantly from their 3D counterparts [1]. The step components ofthe dislocations give rise to a pronounced buckling of the bilayerin order to release strain energy. All dislocations split intoequally-spaced partials due to the absence of a stacking faultenergy, a peculiar property of bilayer graphene. Finally, in 2Dmaterials the strain energy induced by a dislocation does not divergewith sample size as in 3D, but remains finite.In the SoS project we will extend our previous characterization of thestructural properties of 2D dislocations in bilayer graphene [1] tostudy now their dynamical behavior: How do dislocations move? How dothey overcome obstacles (e.g. atomic defects within the graphene layers)?How do networks of dislocations behave? Transferring the establishedknowledge for 3D dislocations to their 2D counterparts is up to nowa completely unexplored area. The study of plastic deformation inreduced dimensionality has the promise of becoming a fascinatingplayground for atomistic simulations [3].[1] B. Butz, C. Dolle, F. Niekiel, K. Weber, D. Waldmann, H.B. Weber, B. Meyer, E. Spiecker, Nature 505 (2014) 533.[2] A. Kolmogorov, V. Crespi, Phys. Rev. B 71 (2005) 235415.[3] L.A. Zepeda-Ruiz, A. Stukowski, T. Oppelstrup, V.V. Bulatov, Nature 550 (2017) 492.

Impressum, Conny Wendler