title: Hubbard gap modulation in vanadium dioxide nanoscale tunnel junctions.
abstract: We locally investigate the electronic transport through individual tunnel junctions containing a 10 nm thin film of vanadium dioxide (VO2) across its thermally induced phase transition. The insulator-to-metal phase transition in the VO2 film collapses the Hubbard gap (experimentally determined to be 0.4 ± 0.07 V), leading to several orders of magnitude change in tunnel conductance. We quantitatively evaluate underlying transport mechanisms via theoretical quantum mechanical transport calculations which show excellent agreement with the experimental results.
authors.affiliation: Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Huefner
authors.forename: Ram Krishna
authors.initials: RK
authors.lastname: Ghosh
authors.forename: Eugene
authors.initials: E
authors.lastname: Freeman
authors.forename: Nikhil
authors.initials: N
authors.lastname: Shukla
authors.forename: Hanjong
authors.initials: H
authors.lastname: Paik
authors.forename: Darrell G
authors.initials: DG
authors.lastname: Schlom
authors.forename: Suman
authors.initials: S
authors.lastname: Datta
keywords: Atomic force microscopy; density functional theory; metal−insulator transition; non-equilibrium Green’s function; tunnel junction; vanadium dioxide