TY - JOUR
T1 - Fermi surface topology in a metallic phase of VO2 thin films grown on TiO2(001) substrates
AU - Muraoka, Yuji
AU - Nagao, Hiroki
AU - Yao, Yuichiro
AU - Wakita, Takanori
AU - Terashima, Kensei
AU - Yokoya, Takayoshi
AU - Kumigashira, Hiroshi
AU - Oshima, Masaharu
N1 - Funding Information:
There is extensive debate regarding whether the origin of the d|| band splitting is an electron–phonon interaction (Peierls transition)5–8, an electron–electron interaction (Mott transition)9–13, or a combination of the two14–16. With regard to Peierls transition, Gupta et al.17performed a first-principle band calculation using the linear-combination-of-atomic-orbitals (LCAO) method and demonstrated tha→t for the metallic phase of VO2, the lowest d|| band FS exhibits certain nesting features with a nesting vector →q = 2 k F = ΓR. Their work indicates that the charge-density waves (CDWs) are significant for the origin of the transition. This prediction was supported by studies of X-ray diffuse scattering18. Apart from X-ray studies, various experimental and theoretical studies support the importance of the electron–phonon interaction19,20. Notwithstanding these intensive works, the likelihood of Peierls transition underlying the MIT is still under debate. This is because there is no experimental result of FS topology of VO2. The deficiency of experimental data renders it difficult to verify whether Peierls transition underlies the MIT.
Publisher Copyright:
© 2018, The Author(s).
PY - 2018/12/1
Y1 - 2018/12/1
N2 - 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 q→ = ΓR, as predicted by the calculation. Our results strongly indicate the formation of the charge-density wave with q→ = ΓR and thus, the importance of Peierls transition for the mechanism of the MIT in VO2.
AB - 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 q→ = ΓR, as predicted by the calculation. Our results strongly indicate the formation of the charge-density wave with q→ = ΓR and thus, the importance of Peierls transition for the mechanism of the MIT in VO2.
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U2 - 10.1038/s41598-018-36281-8
DO - 10.1038/s41598-018-36281-8
M3 - Article
C2 - 30559393
AN - SCOPUS:85058731591
VL - 8
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
IS - 1
M1 - 17906
ER -