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)