Thickness dependence of electronic structures in v O2 ultrathin films: Suppression of the cooperative Mott-Peierls transition

D. Shiga, B. E. Yang, N. Hasegawa, T. Kanda, R. Tokunaga, K. Yoshimatsu, R. Yukawa, M. Kitamura, K. Horiba, H. Kumigashira

Research output: Contribution to journalArticlepeer-review

Abstract

Through in situ photoemission spectroscopy, we investigated the change in the electronic structures and V-V dimerization of dimensionality-controlled VO2 films coherently grown on TiO2(001) substrates. In the nanostructured films, the balance between the instabilities of a bandlike Peierls transition and a Mott transition is controlled as a function of thickness. The characteristic spectral change associated with temperature-driven metal-insulator transition in VO2 thick films holds down to 1.5 nm (roughly corresponding to five V atoms along the [001] direction), whereas VO2 films of less than 1.0 nm exhibit insulating nature without the V-V dimerization characteristic of VO2. These results suggest that the delicate balance between a Mott instability and a bandlike Peierls instability is modulated at a scale of a few nanometers by the dimensional crossover effects and confinement effects, which consequently induce the complicated electronic phase diagram of ultrathin VO2 films.

Original languageEnglish
Article number115114
JournalPhysical Review B
Volume102
Issue number11
DOIs
Publication statusPublished - 2020 Sep

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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