Magnetotransport Properties of Quasi-Free Standing Epitaxial Graphene Bilayer on SiC: Evidence for Bernal Stacking

We investigate the magnetotransport properties of quasi-free standing epitaxial graphene bilayer on SiC, grown by atmospheric pressure graphitization in Ar, followed by H$_2$ intercalation. At the charge neutrality point the longitudinal resistance shows an insulating behavior, which follows a temperature dependence consistent with variable range hopping transport in a gapped state. In a perpendicular magnetic field, we observe quantum Hall states (QHSs) both at filling factors ($ u$) multiple of four ($ u=4, 8, 12$), as well as broken valley symmetry QHSs at $ u=0$ and $ u=6$. These results unambiguously show that the quasi-free standing graphene bilayer grown on the Si-face of SiC exhibits Bernal stacking.