Interlayer electronic transport in bilayer graphene systems

Weak interlayer coupling in 2-dimensional layered materials such as graphene gives rise to rich mechanical and electronic properties, in particular in the case where the two atomic lattices at the interface are rotated with respect to one another. The reduced crystal symmetry leads to anti-correlations and cancellations of the atomic interactions across the interface, leading to low friction¹ and low interlayer electrical transport². Using our recent nanomanipulation technology, based on atomic force microscopy, we show that combined electro-mechanical characterization can uniquely address open fundamental questions related to electronic charge transport^2-3 through stacking faulted structures.  To this end, we studied experimentally and theoretically the interlayer charge transport in twisted bilayer graphene systems separately for edges and bulk parts. We find that interlayer edge currents are several orders of magnitude larger than in the bulk and therefore govern the transport up until very large critical diameters depending on the potential across the adjacent layers and the angular mismatch angle. In addition, we show that the strong edge transport across the interface is governed by strong quantum mechanical interference effects as opposed to simple interlayer atomic interactions.

[1] E. Koren et al., Science, 6235 (2015) 679.

[2] E. Koren et al., Nature Nanotech., 9 (2016) 752.

[3] D. Dutta et al., Nature Comm, 11 (2020) 4746.

Link to the seminar