Evidence for incompressible states in a metal-graphene tunnel junction in high magnetic field

Abstract

We present transport measurements of tunnel junctions made between Cu and graphene in a magnetic field. We observe a transition to a Landau level like structure at high fields, as well as a set of sharp features in the tunneling spectra that shift with gate and tunnel probe voltage along the lines of constant charge density. We explain the sharp features with the formation of degeneracy split localized Landau levels, and addition of electrons to those levels one by one. A large capacitive coupling to the tunnel probe also increases the gate voltage spacing between the Landau levels.

Direct probing of density of states of reduced graphene oxides in a wide voltage range by tunneling junction

“…8 Though the STS measurement can probe local DOS on graphene surface, a large fluctuation in data owing to tip conditions and tip-to-sample separation discourages its employment in band structure investigations. The technique of tunneling junctions on graphene is developed [9][10][11][12] recently to probe the band structure variation.…”