Correlation Between Metal-Insulator Transition Characteristics and Electronic Structure Changes in Vanadium Oxide Thin Films

Journal Article · Tue Jan 01 00:00:00 EST 2008 · Physical Review B: Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.77.195442· OSTI ID:960021

Ruzmetov, D; Senanayake, S; Narayanamurti, V; Ramanathan, S

We correlate electron transport data directly with energy band structure measurements in vanadium oxide thin films with varying V-O stoichiometry across the VO2 metal-insulator transition. A set of vanadium oxide thin films were prepared by reactive dc sputtering from a V target at various oxygen partial pressures (O2 p.p.). Metal-insulator transition (MIT) characteristic to VO2 can be seen from the temperature dependence of electrical resistance of the films sputtered at optimal O2 p.p. Lower and higher O2 p.p. result in disappearance of the MIT. The results of the near edge x-ray absorption fine structure spectroscopy of the O K edge in identical VO films are presented. Redistribution of the spectral weight from {sigma}* to {pi}* bands is found in the vanadium oxide films exhibiting stronger VO2 MIT. This is taken as evidence of the strengthening of the metal-metal ion interaction with respect to the metal-ligand and indirect V-O-V interaction in vanadium oxide films featuring sharp MIT. We also observe a clear correlation between MIT and the width and area of the lower {pi}* band, which is likely to be due to the emergence of the d|| band overlapping with {pi}*. The strengthening of this d|| band near the Fermi level only in the vanadium oxide compounds displaying the MIT points out the importance of the role of the d|| band and electron correlations in the phase transition.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: DE-AC02-98CH10886
• OSTI ID: 960021
• Report Number(s): BNL-83007-2009-JA; PRBMDO; TRN: US1005877
• Journal Information: Physical Review B: Condensed Matter and Materials Physics, Vol. 77, Issue 19; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
ELECTRIC CONDUCTIVITY
ELECTRON CORRELATION
ELECTRONIC STRUCTURE
ELECTRONS
FERMI LEVEL
FINE STRUCTURE
OXYGEN
PARTIAL PRESSURE
SPECTROSCOPY
SPUTTERING
STOICHIOMETRY
TARGETS
TEMPERATURE DEPENDENCE
THIN FILMS
TRANSPORT
VANADIUM OXIDES
national synchrotron light source