Effect of ferroelectric fluctuations on superconductivity at oxide interfaces

• Project/Area Number: 18K04940
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 29020:Thin film/surface and interfacial physical properties-related
• Research Institution: Okayama University
• Principal Investigator: Eguchi Ritsuko 岡山大学, 異分野基礎科学研究所, 助教 (50415098)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: 超伝導 / 酸化物界面 / 強誘電性 / 酸化物薄膜界面 / 強誘電特性

Outline of Final Research Achievements

In order to introduce ferroelectric fluctuations into the superconducting properties at the LaAlO3/SrTiO3 interface, LaAlO3/CaxSr1-xTiO3 was fabricated, in which the substrate was replaced SrTiO3 known as a quantum paraelectric material with CaxSr1-xTiO3 showing a ferroelectric phase transition. The anomalies associated with the ferroelectric phase transition were observed in the temperature dependence of resistivity at the normal state, and then the superconducting transition was observed at a lower temperature. The maximum value of the superconducting transition temperature (Tc) was slightly higher than that of the LaAlO3/SrTiO3 interface system. It was clarified that the phase diagram of Tc with respect to the conductivity in the normal state was different from that of the LaAlO3/SrTiO3 interface system.

Academic Significance and Societal Importance of the Research Achievements

酸素欠損を持つバルクのCaxSr1-xTiO3-dは強誘電相転移を示しさらに低温では超伝導を示すことが報告された。この報告により強誘電性揺らぎの超伝導への影響が議論され、強誘電性揺らぎがTcの上昇に効果的に働くのではないかという予想が理論的になされた。このようなシナリオは、銅酸化物や鉄系の高温超伝導体において、超伝導が反強磁性相近傍に出現するということに類似している。このように様々な電子物性相において、一見悪影響を及ぼすと予想される電子物性相の相境界近傍で新奇な物性や機能が現れるということは物性研究において大変興味深いポイントであり、新たな機能を創出するプラットフォームとなり得ると期待される。

Research Products

• [Int'l Joint Research] ジュネーブ大学(スイス)
• [Int'l Joint Research] ジュネーブ大学(スイス)
• [Int'l Joint Research] ジュネーブ大学(スイス)
• [Journal Article] Emergence of a Pressure-Driven Superconducting Phase in Ba0.77Na0.23Ti2Sb2O (2021)
  • Author(s): Taguchi Tomoya、Wang Yanan、Yang Xiaofan、Li Huan、Takabayashi Yasuhiro、Hayashi Kouichi、Miyazaki Takafumi、Liao Yen-Fa、Ishii Hirofumi、Goto Hidenori、Eguchi Ritsuko、Kubozono Yoshihiro
  • Journal Title: Inorganic Chemistry Volume: 60 Issue: 6 Pages: 3585-3592
  • DOI: 10.1021/acs.inorgchem.0c02836
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Superconductivity in topological insulator β-PdBi2 under pressure (2021)
  • Author(s): A. Suzuki, T. Taguchi, H. Li, Y. Wang, H. Ishii, Y.-F. Liao, H. Goto, R. Eguchi, Y. Kubozono
  • Journal Title: Journal of Physics: Condensed Matter Volume: 33 Issue: 13 Pages: 135702-135702
  • DOI: 10.1088/1361-648x/abd99c
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A new protocol for the preparation of superconducting KBi2 (2020)
  • Author(s): Li Huan、Wang Yanan、Aoki Yutaro、Nishiyama Saki、Yang Xiaofan、Taguchi Tomoya、Miura Akari、Suzuki Ai、Zhi Lei、Goto Hidenori、Eguchi Ritsuko、Kambe Takashi、Liao Yen-Fa、Ishii Hirofumi、Kubozono Yoshihiro
  • Journal Title: RSC Advances Volume: 10 Issue: 45 Pages: 26686-26692
  • DOI: 10.1039/d0ra04541a
  • NAID: 120006953499
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Structure and superconducting properties of multiple phases of (NH3) y AE x FeSe (AE: Ca, Sr and Ba) (2020)
  • Author(s): Li Huan、Wang Yanan、Yang Xiaofan、Taguchi Tomoya、Zhi Lei、Goto Hidenori、Eguchi Ritsuko、Ishii Hirofumi、Liao Yen-Fa、Kubozono Yoshihiro
  • Journal Title: Journal of Physics: Condensed Matter Volume: 32 Issue: 39 Pages: 395704-395704
  • DOI: 10.1088/1361-648x/ab9911
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Band Engineering of Bilayer Graphene through Combination of Direct Electron Transfer and Electrostatic Gating (2020)
  • Author(s): Zhi Lei、Goto Hidenori、Takai Akihisa、Miura Akari、Hamao Shino、Eguchi Ritsuko、Nishikawa Takao、Tokito Shizuo、Kubozono Yoshihiro
  • Journal Title: The Journal of Physical Chemistry C Volume: 124 Issue: 43 Pages: 24001-24008
  • DOI: 10.1021/acs.jpcc.0c07537
  • Peer Reviewed
• [Journal Article] Superconducting behavior of BaTi2Bi2O and its pressure dependence (2020)
  • Author(s): Wang Yanan、Li Huan、Taguchi Tomoya、Suzuki Ai、Miura Akari、Goto Hidenori、Eguchi Ritsuko、Miyazaki Takafumi、Liao Yen-Fa、Ishii Hirofumi、Kubozono Yoshihiro
  • Journal Title: Physical Chemistry Chemical Physics Volume: 22 Issue: 40 Pages: 23315-23322
  • DOI: 10.1039/d0cp04771f
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Superconductivity in Bi2-xSbxTe3-ySey (x = 1.0 and y = 2.0) under pressure (2020)
  • Author(s): He Tong、Yang Xiaofan、Taguchi Tomoya、Zhi Lei、Miyazaki Takafumi、Kobayashi Kaya、Akimitsu Jun、Ishii Hirofumi、Liao Yen-Fa、Goto Hidenori、Eguchi Ritsuko、Kubozono Yoshihiro
  • Journal Title: Journal of Physics: Condensed Matter Volume: 32 Issue: 46 Pages: 465702-465702
  • DOI: 10.1088/1361-648x/abaad2
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Inhomogeneous superconductivity in thin crystals of FeSe1－xTex (x=1.0, 0.95, and 0.9) (2020)
  • Author(s): Ritsuko Eguchi, Megumi Senda, Eri Uesugi, Hidenori Goto, Akihiko Fujiwara, Yasuhiko Imai, Shigeru Kimura, Takashi Noji, Yoji Koike, Yoshihiro Kubozono
  • Journal Title: Materials Research Express Volume: 7 Issue: 3 Pages: 036001-036001
  • DOI: 10.1088/2053-1591/ab7c85
  • NAID: 120006825998
  • Peer Reviewed / Open Access
• [Journal Article] Superconducting behavior of a new metal iridate compound, SrIr2, under pressure (2020)
  • Author(s): Xiaofan Yang, Huan Li, Tong He, Tomoya Taguchi, Yanan Wang, Hidenori Goto, Ritsuko Eguchi, Rie Horie, Kazumasa Horigane, Kaya Kobayashi, Jun Akimitsu, Hirofumi Ishii, Yen Fa Liao, Hitoshi Yamaoka, Yoshihiro Kubozono
  • Journal Title: Journal of Physics Condensed Matter Volume: 32 Issue: 2 Pages: 025704-025704
  • DOI: 10.1088/1361-648x/ab4605
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Preparation and characterization of superconducting Ba1-xCsxTi2Sb2O, and its pressure dependence of superconductivity (2019)
  • Author(s): Wang Yanan, Yang Xiaofan, Taguchi Tomoya, Li Huan, He Tong, Goto Hidenori, Eguchi Ritsuko, Miyazaki Takafumi, Liao Yen-Fa, Ishii Hirofumi, Kubozono Yoshihiro
  • Journal Title: JAPANESE JOURNAL OF APPLIED PHYSICS Volume: 58 Issue: 11 Pages: 110603-110603
  • DOI: 10.7567/1347-4065/ab4ef5
  • NAID: 210000157392
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Pressure-induced superconductivity in Bi2-xSbxTe3-ySey (2019)
  • Author(s): Tong He, Xiaofan Yang, Tomoya Taguchi, Teppei Ueno, Kaya Kobayashi, Jun Akimitsu, Hitoshi Yamaoka, Hirofumi Ishii, Yen-Fa Liao, Hiromi Ota, Hidenori Goto, Ritsuko Eguchi, Kensei Terashima, Takayoshi Yokoya, Harald O. Jeschke, Xianxin Wu, Yoshihiro Kubozono
  • Journal Title: PHYSICAL REVIEW B Volume: 100 Issue: 9 Pages: 094525-094525
  • DOI: 10.1103/physrevb.100.094525
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Fabrication of flexible high-performance organic field-effect transistors using phenacene molecules and their application toward flexible CMOS inverters (2019)
  • Author(s): Pompei Emanuela、Turchetti Claudio、Hamao Shino、Miura Akari、Goto Hidenori、Okamoto Hideki、Fujiwara Akihiko、Eguchi Ritsuko、Kubozono Yoshihiro
  • Journal Title: Journal of Materials Chemistry C Volume: 印刷中 Issue: 20 Pages: 6022-6033
  • DOI: 10.1039/c8tc05824e
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Synthesis of the extended phenacene molecules, [10]phenacene and [11]phenacene, and their performance in a field-effect transistor (2019)
  • Author(s): Okamoto Hideki、Hamao Shino、Eguchi Ritsuko、Goto Hidenori、Takabayashi Yasuhiro、Yen Paul Yu-Hsiang、Liang Luo Uei、Chou Chia-Wei、Hoffmann Germar、Gohda Shin、Sugino Hisako、Liao Yen-Fa、Ishii Hirofumi、Kubozono Yoshihiro
  • Journal Title: Scientific Reports Volume: 9 Issue: 1 Pages: 4009-4009
  • DOI: 10.1038/s41598-019-39899-4
  • NAID: 120006777515
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Preparation and characterization of a new metal-intercalated graphite superconductor (2018)
  • Author(s): Yang Xiaofan、Taguchi Tomoya、Wang Yanan、He Tong、Uchiyama Takaki、Takai Akihisa、Zhi Lei、Miyazaki Takafumi、Goto Hidenori、Eguchi Ritsuko、Ishii Hirofumi、Liao Yen-Fa、Yamaoka Hitoshi、Kubozono Yoshihiro
  • Journal Title: Materials Research Express Volume: 6 Issue: 1 Pages: 016003-016003
  • DOI: 10.1088/2053-1591/aae9d2
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Synthesis and Physical Properties of Niobium Oxide Dihalide NbOBr2 (2021)
  • Author(s): Eguchi Ritsuko
  • Organizer: International Meeting on Thin Film Interfaces and Composite Crystals
  • Int'l Joint Research / Invited
• [Presentation] Conductivity and superconductivity at LaAlO3/Ca-doped SrTiO3 interfaces (2019)
  • Author(s): Ritsuko Eguchi, Margherita Boselli, Adrien Waelchli, Gernot Scheerer, Danfeng Li, Stefano Gariglio, Jean-Marc Triscone
  • Organizer: Workshop ‘Progress in Superconductivity Research’
• [Presentation] Superconductivity at LaAlO3/Sr1-xCaxTiO3 interfaces (2018)
  • Author(s): Ritsuko Eguchi, Margherita Boselli, Adrien Waelchli, Stefano Gariglio, Jean-Marc Triscone
  • Organizer: European Materials Research Society (E-MRS) 2018 Fall meeting
  • Int'l Joint Research
• [Presentation] LaAlO3/Sr1-xCaxTiO3界面の超伝導特性 (2018)
  • Author(s): 江口律子, Margherita Boselli, Adrien Waelchli, Gernot Scheerer, Danfeng Li, Stefano Gariglio, Jean-Marc Triscone
  • Organizer: 日本物理学会2018年秋季大会