Wet processing changes stacking order in multilayer graphene flakes

Quantum transport in multilayer graphene is interesting in many aspects. For example, it was shown that in ultraclean samples of graphene bilayers [1] and recently also multilayers[2], the exchange interaction leads to a novel phase, who’s nature is currently still under debate. At the heart of answering this question is knowledge of the local stacking order during a charge transport experiment. Here, we show that the structuring of metal contacts can induce a non-local transition from ABC to ABA stacking. This stacking has been identified by spatially resolved Raman and scattering SNOM measurements. We discuss possible reasons for this transformation.
[1] R.T. Weitz, M.T. Allen, B.E. Feldman, J. Martin, and A. Yacoby, “Broken-symmetry states in doubly gated suspended bilayer graphene”, Science 330, 812 (2010)
[2] Y. Nam, D.-K. Ki, M. Koshino, E. McCann and A.F Morpurgo, “Interaction-induced insulating state in thick multilayer graphene”, 2D Mater. 3 045014 (2016)