Structure of twisted and buckled bilayer graphene
2017 (English)In: 2D MATERIALS, ISSN 2053-1583, Vol. 4, no 1, 015018Article in journal (Refereed) Published
We study the atomic structure of twisted bilayer graphene, with very small mismatch angles (theta similar to 0.28(0)), a topic of intense recent interest. We use simulations, in which we combine a recently presented semi-empirical potential for single-layer graphene, with a new term for out-of-plane deformations, (Jain et al. 2015 J. Phys. Chem. C119 9646) and an often-used interlayer potential (Kolmogorov et al 2005 Phys. Rev. B 71 235415). This combination of potentials is computationally cheap but accurate and precise at the same time, allowing us to study very large samples, which is necessary to reach very small mismatch angles in periodic samples. By performing large scale atomistic simulations, we show that the vortices appearing in the Moire pattern in the twisted bilayer graphene samples converge to a constant size in the thermodynamic limit. Furthermore, the well known sinusoidal behavior of energy no longer persists once the misorientation angle becomes very small (theta < 1(0)). We also show that there is a significant buckling after the relaxation in the samples, with the buckling height proportional to the system size. These structural properties have direct consequences on the electronic and optical properties of bilayer graphene.
Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2017. Vol. 4, no 1, 015018
bilayer graphene, elastic potential, vortices, local energy, buckling, Moire pattern
IdentifiersURN: urn:nbn:se:kth:diva-198862DOI: 10.1088/2053-1583/4/1/015018ISI: 000388633300001OAI: oai:DiVA.org:kth-198862DiVA: diva2:1059730
QC 201612232016-12-232016-12-222016-12-23Bibliographically approved