Transport Spectroscopy of Sublattice-Resolved Resonant Scattering in Hydrogen-Doped Bilayer Graphene*

Two-dimensional materials are atomically thin membranes with extreme surface sensitivity, enabling unprecedented tuning of their electronic, magnetic and spintronic properties via surface modification. In particular, hydrogenation has emerged as a powerful technique to alter the properties of graphene, which is predicted to induce band-gap, spin-orbit coupling, as well as magnetism.
We perform hydrogen adatom doping of bilayer graphene in ultrahigh vacuum, and report sublattice-dependent resonant scattering through systematic in-situ transport measurement. By alternating between adatom deposition and transport measurement, both at 21K, we observe the gradual emergence of two additional peaks in the gate dependent resistance away from the charge neutrality point. Through a combination of density functional theory and Boltzmann transport theory, we attribute these two peaks to resonant scattering states associated with hydrogen adsorbed on different sublattices. Subsequent annealing study shows the possibility of sublattice selective hydrogenation, which is very interesting for developing ferromagnetic ordering in hydrogen-doped graphene.