Thickness dependence of electronic and crystal structures in VO${}_2$ ultrathin films: suppression of the collaborative Mott-Peierls transition

Abstract

Through $insitu$ photoemission spectroscopy, we investigated the change in the electronic and crystal structures of dimensionality-controlled VO${}_2$ films coherently grown on TiO${}_2$(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 VO${}_2$ thick films holds down to 1.5 nm (roughly corresponding to five V atoms along the [001] direction), whereas VO${}_2$ films of less than 1.0 nm exhibit insulating nature without V-V dimerization. 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 VO${}_2$ films.

arXiv comment30 pages, 4 main figures, 4 supplementary figures

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Cited by in corpus (5)

• Bilayer Vanadium Dioxide Thin Film with Elevated Transition Temperatures and High Resistance Switching
• Electronic phase diagram of Cr-doped VO2 epitaxial films studied by in situ photoemission spectroscopy
• Competitive coexistence of ferromagnetism and metal--insulator transition of VO${}_2$ nanoparticles
• Interface-induced collective phase transition in VO2-based bilayers studied by layer selective spectroscopy
• Confinement-Induced Isosymmetric Metal-Insulator Transition in Ultrathin Epitaxial V2O3 Films