title: Selective scanning tunneling microscope light emission from rutile phase of VO2.
abstract: We observed scanning tunneling microscope light emission (STM-LE) induced by a tunneling current at the gap between an Ag tip and a VO2 thin film, in parallel to scanning tunneling spectroscopy (STS) profiles. The 34 nm thick VO2 film grown on a rutile TiO2 (0 0 1) substrate consisted of both rutile (R)- and monoclinic (M)-structure phases of a few 10 nm-sized domains at room temperature. We found that STM-LE with a certain photon energy of 2.0 eV occurs selectively from R-phase domains of VO2, while no STM-LE was observed from M-phase. The mechanism of STM-LE from R-phase VO2 was determined to be an interband transition process rather than inverse photoemission or inelastic tunneling processes.
authors.affiliation: GREMAN, UMR 7347 CNRS/Université François Rabelais de Tours, 37200 Tours, France.
authors.forename: Joe
authors.initials: J
authors.lastname: Sakai
authors.forename: Masashi
authors.initials: M
authors.lastname: Kuwahara
authors.forename: Masaki
authors.initials: M
authors.lastname: Hotsuki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Katano
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Uehara