Magnetic Response of a Twisted Bilayer Graphene Barrier.

Twisted bilayer graphene (TBG) has recently drawn great attention because of the wide variety of novel electronic and optical properties. Behind the new phenomena, for low twist angle, we can find the emergence of flat-bands produced by the localization of the electronic wave-function on the AA-stacked regions. In this regime, a paramagnetic response to an in-plane magnetic field is expected. Here, to induce the above-mentioned response electrically we created a TBG barrier putting a graphene flake on top of biased graphene nanoribbon. Our results [1] show that for low twist angles the applied electric field induces the formation of a well-defined Moiré superlattice of in-plane magnetic moments whose magnitude and orientation can be tuned the source-drain voltage. Our results are robust against lattice relaxation, lattice orientation and edge vacancies.

[1] D. A. Bahamon, G. Gómez-Santos, and T. Stauber, Nanoscale 12, 15383 (2020).