Fractal Nature of Metallic and Insulating Domain Configurations in a VO2 Thin Film Revealed by Kelvin Probe Force Microscopy

Ahrum Sohn; Teruo Kanki; Kotaro Sakai; Hidekazu Tanaka; Dong Wook Kim

doi:10.1038/srep10417

Fractal Nature of Metallic and Insulating Domain Configurations in a VO₂ Thin Film Revealed by Kelvin Probe Force Microscopy

Ahrum Sohn, Teruo Kanki, Kotaro Sakai, Hidekazu Tanaka, Dong Wook Kim

Department of Physics

Research output: Contribution to journal › Article › peer-review

34 Scopus citations

Abstract

We investigated the surface work function (W_S) 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 W_S values, throughout the metal-insulator transition. The metallic fraction, estimated from W_S 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.

Original language	English
Article number	10417
Journal	Scientific Reports
Volume	5
DOIs	https://doi.org/10.1038/srep10417
State	Published - 18 May 2015

Bibliographical note

Funding Information:
A.S. and D.K. acknowledge the support from Basic Science Research Program and the Quantum Metamaterials Research Center (QMMRC) through the National Research Foundation of Korea Grant (NRF-2013R1A1A2063744, NRF-2008-0061893). T.K., K.S. and H.T. acknowledge the support from Grant-in-Aid for Scientific Research A (No. 26246013) and Grant-in-Aid for Scientific Research B (No. 25286058) from the Japan Society for Promotion of Science (JSPS), and the Nanotechnology Platform Project (Nanotechnology Open Facilities in Osaka University) of MEXT (F-14-OS-0010, S-14-OS-0007).

Publisher Copyright:
© 2015, Nature Publishing Group. All rights reserved.

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10.1038/srep10417

Cite this

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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.",

author = "Ahrum Sohn and Teruo Kanki and Kotaro Sakai and Hidekazu Tanaka and Kim, {Dong Wook}",

note = "Funding Information: A.S. and D.K. acknowledge the support from Basic Science Research Program and the Quantum Metamaterials Research Center (QMMRC) through the National Research Foundation of Korea Grant (NRF-2013R1A1A2063744, NRF-2008-0061893). T.K., K.S. and H.T. acknowledge the support from Grant-in-Aid for Scientific Research A (No. 26246013) and Grant-in-Aid for Scientific Research B (No. 25286058) from the Japan Society for Promotion of Science (JSPS), and the Nanotechnology Platform Project (Nanotechnology Open Facilities in Osaka University) of MEXT (F-14-OS-0010, S-14-OS-0007). Publisher Copyright: {\textcopyright} 2015, Nature Publishing Group. All rights reserved.",

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AU - Tanaka, Hidekazu

AU - Kim, Dong Wook

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