title: Fractal Nature of Metallic and Insulating Domain Configurations in a VO2 Thin Film Revealed by Kelvin Probe Force Microscopy.
abstract: We investigated the surface work function (WS) and its spatial distribution for epitaxial VO2/TiO2 thin films using Kelvin probe force microscopy (KPFM). Nearly grain-boundary-free samples allowed observation of metallic and insulating domains with distinct WS values, throughout the metal-insulator transition. The metallic fraction, estimated from WS maps, describes the evolution of the resistance based on a two-dimensional percolation model. The KPFM measurements also revealed the fractal nature of the domain configuration.
authors.affiliation: Department of Physics, Ewha Womans University, Seoul 120-750, Korea.
authors.forename: Ahrum
authors.initials: A
authors.lastname: Sohn
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Kanki
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Sakai
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Physics, Ewha Womans University, Seoul 120-750, Korea.
authors.forename: Dong-Wook
authors.initials: DW
authors.lastname: Kim