Talk given by

Dr. Sam Shallcross

Theoretische Festkörperphysik

Universität Erlangen

Abstract:

Recently imaged partial dislocations in bilayer graphene [1] have been shown to have a profound
impact on transport properties for the case of bilayer graphene on SiC [2]. We demonstrate that the presence of only a few partial dislocations in high quality suspended bilayer graphene may both destroy the intrinsic minimal conductivity of the structurally perfect bilayer, or even enhance it, depending only on the configuration of the partials. We find that a single partial dislocation is already sufficient to generate both an insulating or conducting state of the bilayer, while three partial configurations yield a wide range of transport states between the minimal conductivity of the pristine bilayer and a fully insulating state. This provides a natural explanation for the peculiar behaviour of ultra-clean suspended bilayer graphene, in which similar samples of high mobility are found in experiment to be either insulating or conducting in nature [3].

[1] B. Butz, C. Dolle, F. Niekiel, K. Weber, D. Waldmann, H. B. Weber, B. Meyer, E. Spiecker,
Nature 505, 533 (2014).
[2] F. Kisslinger, C. Ott, C. Heide, E. Kampert, B. Butz, E. Spiecker, S. Shallcross, H. B. Weber,
Nature Physics 11, 650 (2015).
[3] W. Bao et al. Proceedings of the National Academy of Sciences 109, 10802-10805 (2012)