Even when sandwiched between atomically flat hBN crystals, surprisingly, graphene still exhibits ripples, even in absence of bubbles. These out-of-plane corrugations reduce mobility and suppress weak localization in an in-plane magnetic field. This effect allows extraction of the corrugation volume, in very good agreement with AFM measurements.
Basel - Budapest - Tsukuba as well as Schönenberger - Zumbühl collaboration!
Zihlmann, Makk et al. Phys. Rev. B102, 195404 (Nov 4, 2020)