Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 6: Graphene: Electronic properties, structure and substrate interaction I (joint session O/TT)

O 6.9: Talk

Monday, March 12, 2018, 12:30–12:45, MA 043

Moiré ordered current loops in the graphene twist bilayer — •Dominik Weckbecker and Sam Shallcross — FAU Erlangen-Nürnberg, Institut für Theoretische Physik, Staudtstrasse 7/B2, 91058 Erlangen, Germany

Moiré lattices in layered two dimensional materials possess, in the presence of a magnetic field of 1-5 Tesla, comparable structural and magnetic length scales and, as a consequence, exhibit remarkable magnetic field phenomena such as the recently observed Hofstadter butterfly [1,2].

In this contribution, we present the results of our simulations on twisted bilayer graphene nanoribbons, which were conducted using a semi-empirical tight-binding method [3].

We report novel phenomena arising from this interplay of length scales in the form of an ordered array of permanent current loops throughout a moiré generated by twisting graphene layers [3,4]. Strikingly, these current loops are found at significantly weaker fields than those required to observe the Hofstadter butterfly, and such current loops thus represent an additional low field imprint of the moiré lattice on Landau physics, and an unusual situation in which the field induced currents are found in the bulk of a material.

[1] D. R. Hofstadter, Phys. Rev. B 14, 2239 (1976)

[2] C. R. Dean et al. , Nature 497, 598-602 (2013)

[3] W. Landgraf et al., Phys. Rev. B. 87, 075433 (2013)

[4] manuscript in preparation