Fermi surface topology in a metallic phase of VO2 thin films grown on TiO2(001) substrates

Yuji Muraoka; Hiroki Nagao; Yuichiro Yao; Takanori Wakita; Kensei Terashima; Takayoshi Yokoya; Hiroshi Kumigashira; Masaharu Oshima

doi:10.1038/s41598-018-36281-8

Fermi surface topology in a metallic phase of VO₂ thin films grown on TiO₂(001) substrates

Sci Rep. 2018 Dec 17;8(1):17906. doi: 10.1038/s41598-018-36281-8.

Authors

Yuji Muraoka¹, Hiroki Nagao², Yuichiro Yao², Takanori Wakita³, Kensei Terashima³, Takayoshi Yokoya³, Hiroshi Kumigashira^{4

5}, Masaharu Oshima⁶

Affiliations

¹ Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-naka, Tsushima, Kita-ku, Okayama, 700-8530, Japan. ymuraoka@cc.okayama-u.ac.jp.
² Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Tsushima, Kita-ku, Okayama, 700-8530, Japan.
³ Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-naka, Tsushima, Kita-ku, Okayama, 700-8530, Japan.
⁴ High Energy Accelerator Research Organization (KEK), Photon Factory, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan.
⁵ Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.
⁶ The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan.

Abstract

Since the first observation of the metal-to-insulator transition (MIT), VO₂ has attracted substantial attention in terms of whether this transition is impelled by electron-phonon interaction (Peierls transition) or electron-electron interaction. Regarding Peierls transition, it has been theoretically predicted that the Fermi surface (FS) cross-section exhibits certain nesting features for a metallic phase of VO₂. Various experimental studies related to the nesting feature have been reported. Nevertheless, there is no experimental result on FS topology. In this work, we determine the FS topology of the metallic phase of VO₂ through studies of VO₂ epitaxial thin films on TiO₂(001) substrates, using synchrotron radiation angle-resolved photoemission spectroscopy (ARPES). Three electron pockets around Γ are observed in band structures along the Γ-X direction. These three bands form electron surfaces around Γ in the ΓXRZ plane. Furthermore, the lowest energy band FS exhibits the nesting feature corresponding to a nesting vector [Formula: see text] = ΓR, as predicted by the calculation. Our results strongly indicate the formation of the charge-density wave with [Formula: see text] = ΓR and thus, the importance of Peierls transition for the mechanism of the MIT in VO₂.