Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 97: Graphene: Structure (jointly with O, HL)

TT 97.9: Vortrag

Donnerstag, 19. März 2015, 12:30–12:45, MA 041

Structure, strain distribution and energetics of basal-plane dislocations in bilayer graphene — •Konstantin Weber and Bernd Meyer — Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, FAU Erlangen-Nürnberg

A recent TEM study [1] demonstrated that substrate-grown graphene bilayers are typically not perfect in registry, but contain a high concentration of basal-plane dislocations. Using atomistic simulations based on the registry-dependent potential of Kolmogorov and Crespi [2] and the classical AIREBO potential we investigated the atomic structure and the properties of the 4 different types of dislocations with shortest possible Burgers vector in bilayer graphene, the thinnest imaginable crystal that can host such 1D defects. We find that each of the 4 different dislocations splits into two partial dislocations. The partials are equally spaced due to the absence of a stacking fault energy, a peculiar property of bilayer graphene. Furthermore, partials with a step component give rise to a pronounced buckling of the graphene bilayer. An analysis of the atomic structure, local strain distribution, disregistry and dislocation energy of the dislocations will be given and we will highlight how their properties differ from textbook examples of dislocations in 3D crystals.

[1] B.Butz, C. Dolle, F. Niekiel, K. Weber, D. Waldmann, H.B. Weber,
  B. Meyer, E. Spieker, Nature 505, 533 (2014).
[2] A. Kolmogorov, V. Crespi, Phys. Rev. B 71, 235415 (2005).