Abstract: Strain superlattices, i.e. non-uniform periodic strain profiles, have been predicted to lead to novel quantum phenomena in graphene through the generation of gauge fields called pseudomagnetic fields (PMF). PMF can create pseudo-Landau levels in the band structure and also lift the sublattice symmetry of graphene, and hence break the valley degeneracy of charge carriers. However, there have been few experimental realizations of custom, reproducible strain superlattice potentials in graphene to study the effects of PMF in transport.
In this talk, I will present a detailed study of how PMF can modify the transport properties of a graphene strain superlattice, created by stacking graphene on self-assembled, quasiperiodic nanosphere arrays. We observe several PMF-induced transport signatures - moderate-field Landau quantization in graphene nanoribbons, quantum confinement of charge carriers, resistance oscillations due to the formation of pseudo-Landau levels and field-asymmetric transport and unconventional Hall signals due to valley split edge currents.
Apart from improving our fundamental understanding of the effects of PMF on charge carriers, this research will also have broader implications in the field of graphene valleytronics, which relies on the generation and manipulation of valley polarized currents in graphene.