title: Correlation-Driven Insulator-Metal Transition in Near-Ideal Vanadium Dioxide Films.
abstract: We use polarization- and temperature-dependent x-ray absorption spectroscopy, in combination with photoelectron microscopy, x-ray diffraction, and electronic transport measurements, to study the driving force behind the insulator-metal transition in VO_{2}. We show that both the collapse of the insulating gap and the concomitant change in crystal symmetry in homogeneously strained single-crystalline VO_{2} films are preceded by the purely electronic softening of Coulomb correlations within V-V singlet dimers. This process starts 7 K (±0.3  K) below the transition temperature, as conventionally defined by electronic transport and x-ray diffraction measurements, and sets the energy scale for driving the near-room-temperature insulator-metal transition in this technologically promising material.
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Department of Physics, Temple University, 1925 North 12th Street, Philadelphia, Pennsylvania 19130, USA.
authors.forename: A X
authors.initials: AX
authors.lastname: Gray
authors.affiliation: IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA.
authors.forename: J
authors.initials: J
authors.lastname: Jeong
authors.affiliation: IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA.
authors.forename: N P
authors.initials: NP
authors.lastname: Aetukuri
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Van der Waals-Zeeman Institute, University of Amsterdam, 1018XE Amsterdam, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Granitzka
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: R
authors.initials: R
authors.lastname: Kukreja
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: D
authors.initials: D
authors.lastname: Higley
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: T
authors.initials: T
authors.lastname: Chase
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: A H
authors.initials: AH
authors.lastname: Reid
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: H
authors.initials: H
authors.lastname: Ohldag
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Marcus
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: A
authors.initials: A
authors.lastname: Scholl
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Young
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: A
authors.initials: A
authors.lastname: Doran
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Jenkins
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: P
authors.initials: P
authors.lastname: Shafer
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: E
authors.initials: E
authors.lastname: Arenholz
authors.affiliation: IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Samant
authors.affiliation: IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA.
authors.forename: S S P
authors.initials: SS
authors.lastname: Parkin
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: H A
authors.initials: HA
authors.lastname: Dürr