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Mott transition in chain structure of strained VO2 films revealed by coherent phonons.

ABSTRACT: The characteristic of strongly correlated materials is the Mott transition between metal and insulator (MIT or IMT) in the same crystalline structure, indicating the presence of a gap formed by the Coulomb interaction between carriers. The physics of the transition needs to be revealed. Using VO2, as a model material, we observe the emergence of a metallic chain in the intermediate insulating monoclinic structure (M2 phase) of epitaxial strained films, proving the Mott transition involving the breakdown of the critical Coulomb interaction. It is revealed by measuring the temperature dynamics of coherent optical phonons with separated vibrational modes originated from two substructures in M2: one is the charge-density-wave, formed by electron-phonon (e-ph) interaction, and the other is the equally spaced insulator-chain with electron-electron (e-e) correlations.

SUBMITTER: Slusar TV

PROVIDER: S-EPMC5700180 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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Mott transition in chain structure of strained VO<sub>2</sub> films revealed by coherent phonons.

Slusar Tetiana V TV Cho Jin-Cheol JC Lee Hyang-Rok HR Kim Ji-Wan JW Yoo Seung Jo SJ Bigot Jean-Yves JY Yee Ki-Ju KJ Kim Hyun-Tak HT

Scientific reports 20171122 1

The characteristic of strongly correlated materials is the Mott transition between metal and insulator (MIT or IMT) in the same crystalline structure, indicating the presence of a gap formed by the Coulomb interaction between carriers. The physics of the transition needs to be revealed. Using VO<sub>2</sub>, as a model material, we observe the emergence of a metallic chain in the intermediate insulating monoclinic structure (M2 phase) of epitaxial strained films, proving the Mott transition invo ...[more]

PMID: 29167488

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