Tunneling Response of Graphite-hBN-NbSe2 Planar Junctions

Tunneling current from an electrode to sample is directly proportional to the density of states of the sample at the energy which is biased. This is most clearly determined via scanning tunneling spectroscopy, however this method is not suitable for a growing number of materials that are unstable without encapsulation. By using a 2-dimensional electrode and dielectric, a tunneling spectrum can be measured on an encapsulated sample. A tunneling spectrum from a planar junction can however be smeared by spatial inhomogeneity of the electrode, which can be ameliorated by increasing physical thickness of dielectric. This work examines the tunneling spectrum of mechanically exfoliated graphite to encapsulated NbSe2 with various thicknesses of hBN dielectrics.