Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy

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Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy. / Jepsen, Peter Uhd; Fischer, Bernd M.; Thoman, Andreas; Helm, Hanspeter; Suh, J.Y.; Lopez, René; Haglund jr., R.F.

In: Physical Review B Condensed Matter, Vol. 74, No. 20, 2006, p. 205103.

Research output: Contribution to journalJournal article – Annual report year: 2006Researchpeer-review

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Jepsen, Peter Uhd ; Fischer, Bernd M. ; Thoman, Andreas ; Helm, Hanspeter ; Suh, J.Y. ; Lopez, René ; Haglund jr., R.F. / Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy. In: Physical Review B Condensed Matter. 2006 ; Vol. 74, No. 20. pp. 205103.

Bibtex

@article{b8474464d43f4a26baa35777a1c34e7f,
title = "Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy",
abstract = "We investigate the dielectric properties of a thin VO2 film in the terahertz frequency range in the vicinity of the semiconductor-metal phase transition. Phase-sensitive broadband spectroscopy in the frequency region below the phonon bands of VO2 gives insight into the conductive properties of the film during the phase transition. We compare our experimental data with models proposed for the evolution of the phase transition. The experimental data show that the phase transition occurs via the gradual growth of metallic domains in the film, and that the dielectric properties of the film in the vicinity of the transition temperature must be described by effective-medium theory. The simultaneous measurement of both transmission and phase shift allows us to show that Maxwell-Garnett effective-medium theory, coupled with the Drude conductivity model, can account for the observed behavior, whereas the widely used Bruggeman effective-medium theory is not consistent with our findings. Our results show that even at temperatures significantly above the transition temperature the formation of a uniform metallic phase is not complete.",
keywords = "TRANSPORT, TIME-DOMAIN SPECTROSCOPY, NANOPARTICLES, DIOXIDE, CONSTANTS",
author = "Jepsen, {Peter Uhd} and Fischer, {Bernd M.} and Andreas Thoman and Hanspeter Helm and J.Y. Suh and Ren{\'e} Lopez and {Haglund jr.}, R.F.",
note = "Copyright 2006 American Physical Society",
year = "2006",
doi = "10.1103/PhysRevB.74.205103",
language = "English",
volume = "74",
pages = "205103",
journal = "Physical Review B (Condensed Matter and Materials Physics)",
issn = "1098-0121",
publisher = "American Physical Society",
number = "20",

}

RIS

TY - JOUR

T1 - Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy

AU - Jepsen, Peter Uhd

AU - Fischer, Bernd M.

AU - Thoman, Andreas

AU - Helm, Hanspeter

AU - Suh, J.Y.

AU - Lopez, René

AU - Haglund jr., R.F.

N1 - Copyright 2006 American Physical Society

PY - 2006

Y1 - 2006

N2 - We investigate the dielectric properties of a thin VO2 film in the terahertz frequency range in the vicinity of the semiconductor-metal phase transition. Phase-sensitive broadband spectroscopy in the frequency region below the phonon bands of VO2 gives insight into the conductive properties of the film during the phase transition. We compare our experimental data with models proposed for the evolution of the phase transition. The experimental data show that the phase transition occurs via the gradual growth of metallic domains in the film, and that the dielectric properties of the film in the vicinity of the transition temperature must be described by effective-medium theory. The simultaneous measurement of both transmission and phase shift allows us to show that Maxwell-Garnett effective-medium theory, coupled with the Drude conductivity model, can account for the observed behavior, whereas the widely used Bruggeman effective-medium theory is not consistent with our findings. Our results show that even at temperatures significantly above the transition temperature the formation of a uniform metallic phase is not complete.

AB - We investigate the dielectric properties of a thin VO2 film in the terahertz frequency range in the vicinity of the semiconductor-metal phase transition. Phase-sensitive broadband spectroscopy in the frequency region below the phonon bands of VO2 gives insight into the conductive properties of the film during the phase transition. We compare our experimental data with models proposed for the evolution of the phase transition. The experimental data show that the phase transition occurs via the gradual growth of metallic domains in the film, and that the dielectric properties of the film in the vicinity of the transition temperature must be described by effective-medium theory. The simultaneous measurement of both transmission and phase shift allows us to show that Maxwell-Garnett effective-medium theory, coupled with the Drude conductivity model, can account for the observed behavior, whereas the widely used Bruggeman effective-medium theory is not consistent with our findings. Our results show that even at temperatures significantly above the transition temperature the formation of a uniform metallic phase is not complete.

KW - TRANSPORT

KW - TIME-DOMAIN SPECTROSCOPY

KW - NANOPARTICLES

KW - DIOXIDE

KW - CONSTANTS

U2 - 10.1103/PhysRevB.74.205103

DO - 10.1103/PhysRevB.74.205103

M3 - Journal article

VL - 74

SP - 205103

JO - Physical Review B (Condensed Matter and Materials Physics)

JF - Physical Review B (Condensed Matter and Materials Physics)

SN - 1098-0121

IS - 20

ER -