Structural phase transition between γ-Ti3O5 and δ-Ti3O5 by breaking of a one-dimensionally conducting pathway

Kenji Tanaka, Tomomichi Nasu, Yasuto Miyamoto, Noriaki Ozaki, Shu Tanaka, Toshiaki Nagata, Fumiyoshi Hakoe, Marie Yoshikiyo, Kosuke Nakagawa, Yoshikazu Umeta, Kenta Imoto, Hiroko Tokoro, Asuka Namai, Shin Ichi Ohkoshi

研究成果: Article査読

25 被引用数 (Scopus)

抄録

The phase transition between gamma-trititanium-pentoxide (γ-Ti3O5) and delta-trititanium-pentoxide (δ-Ti3O5) was clarified from both experimental and theoretical viewpoints. With decreasing temperature, the monoclinic I2/c crystal structure of γ-Ti3O5 was found to switch to a monoclinic P2/a crystal structure of δ-Ti3O5 due to lowering of symmetry. Electrical conductivity (σ) measurement shows that γ-Ti3O5 behaves like a metallic conductor with a σ value of 4.7 S cm-1 at 320 K, while δ-Ti3O5 shows a semiconductive property with a σ value of 2.5 × 10-5 S cm-1 at 70 K. Optical measurement also supports that γ-Ti3O5 is a metallic conductor, while δ-Ti3O5 is a semiconductor with a band gap of 0.07 eV. First-principles calculations show that γ-Ti3O5 is a metallic conductor, and the energy state on the Fermi energy is composed of the 3d orbital of Ti and 2p orbital of O with one-dimensional linkage along the crystallographic c-axis. On the contrary, δ-Ti3O5 has a band gap, and the energy state around the Fermi energy is split into the valence band and the conduction band, which are assigned to the lower and upper Hubbard bands, respectively. Thus, the phase transition between γ-Ti3O5 and δ-Ti3O5 is caused by breaking of a one-dimensionally conducting pathway due to a Mott-Hubbard metal-insulator phase transition.

本文言語English
ページ(範囲)653-657
ページ数5
ジャーナルCrystal Growth and Design
15
2
DOI
出版ステータスPublished - 2015 2 4
外部発表はい

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

フィンガープリント 「Structural phase transition between γ-Ti<sub>3</sub>O<sub>5</sub> and δ-Ti<sub>3</sub>O<sub>5</sub> by breaking of a one-dimensionally conducting pathway」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

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