UCLA

Non-planar periodic graphene structures (NPPGS) were fabricated using standard photolithography. CVD graphene was transferred on prepatterned oxide substrates with square and sinusoidal features. Heat treatment techniques were used to improve adhesion between graphene and the substrate which led to the formation of NPPGS. Transport measurements showed an increase in resistivity and a decrease in mean free path which was calculated using the Landauer model. A magnetic field was applied to the NPPGS which, due to the periodic features in the graphene film, creates periodic magnetic barriers in graphene. The sample was rotated with respect to the magnetic field perpendicular to the ripples. An increase in magnetoresisnace was observed as the sample was rotated with respect to the sample. Exact profiles for the effect magnetic field, perpendicular to the graphene film, was determined numerically. Boltzmann transport equation can be used to analyze the effect of different profiles for the magnetic barriers. This can prove the observed resonances in transmission through magnetic barriers for Dirac fermions.