Photoemission study of TiO2/VO2 interfaces

K. Maekawa; M. Takizawa; H. Wadati; T. Yoshida; A. Fujimori; H. Kumigashira; M. Oshima; Y. Muraoka; Y. Nagao; Z. Hiroi

doi:10.1103/PhysRevB.76.115121

paper

Photoemission study of TiO2/VO2 interfaces

arXiv:cond-mat/0611453 · doi:10.1103/PhysRevB.76.115121

Abstract

We have measured photoemission spectra of two kinds of TiO $_{2}$ -capped VO $_{2}$ thin films, namely, that with rutile-type TiO $_{2}$ (r-TiO $_{2}$ /VO $_{2}$ ) and that with amorphous TiO $_{2}$ (a-TiO $_{2}$ /VO $_{2}$ ) capping layers. Below the Metal-insulator transition temperature of the VO $_{2}$ thin films, $\sim 300$ K, metallic states were not observed for the interfaces with TiO $_{2}$ , in contrast with the interfaces between the band insulator SrTiO $_{3}$ and the Mott insulator LaTiO $_{3}$ in spite of the fact that both TiO $_{2}$ and SrTiO $_{3}$ are band insulators with $d^{0}$ electronic configurations and both VO $_{2}$ and LaTiO $_{3}$ are Mott insulators with $d^{1}$ electronic configurations. We discuss possible origins of this difference and suggest the importance of the polarity discontinuity of the interfaces. Stronger incoherent part was observed in r-TiO $_{2}$ /VO $_{2}$ than in a-TiO $_{2}$ /VO $_{2}$ , suggesting Ti-V atomic diffusion due to the higher deposition temperature for r-TiO $_{2}$ /VO $_{2}$ .

5 pages, 6 figures

Photoemission study of TiO2/VO2 interfaces

Abstract

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