Theory of competing hybridization effect and magnetic and multipole states in the rare-earth compounds

• Project/Area Number: 25400362
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: University of the Ryukyus (2015); Niigata University (2013-2014)
• Principal Investigator: Shiina Ryousuke 琉球大学, 理学部, 教授 (30326011)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Project Status: Completed (Fiscal Year 2015)
• Budget Amount: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000); Fiscal Year 2015: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2014: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2013: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
• Keywords: 軌道自由度 / 混成 / 希土類 / 相転移 / 磁性 / 電荷 / 磁場 / 結晶場 / スクッテルダイト / サマリウム / 金属絶縁体転移 / 近藤格子 / 反強磁性 / スピン励起 / 反強磁性秩序 / 電荷秩序 / 四極子 / 電気分極

Outline of Final Research Achievements

This project was designed for investigating the frustrated ordered states that originate from the mixing between conduction and f electrons. Through the course of this study, we have discovered that a spin-charge composite ordered phase is stabilized in an effective Hamiltonian derived from the pf mixing for Sm-ions. This state is found to explain a number of anomalous low-temperature properties of SmRu4P12 which have been known as long-standing puzzles. We have also clarified the global structure of the phase diagram under the strong competition between spin and charge interactions. The proposed ordered state was then identified by a synchrotron-radiation X-ray diffraction experiment by Matsumura et al.. We have further investigated the transport properties of the ordered phase and found a realization of the half-metallic state due to an interference of the two order parameters. A reasonable interpretation of recent transport measurements was given on the basis of this theory.

Research Products

• [Journal Article] Acoustic Emission Measurements on Metal-Hydrogenation Process by Using Electrochemical Charging Cell (2015)
  • Author(s): J.Piao, H. Shoji, T. Murakami, R. Shiina, S. Harada
  • Journal Title: MATERIALS TRANSACTIONS Volume: 56 Issue: 9 Pages: 1496-1500
  • DOI: 10.2320/matertrans.M2015169
  • NAID: 130005094810
  • ISSN: 1345-9678, 1347-5320
  • Peer Reviewed
• [Journal Article] pf Mixing, Competing Interactions, and Unconventional Magnetism in SmRu4P12 (2014)
  • Author(s): Ryousuke Shiina
  • Journal Title: JPS Conf. Proc. Volume: 3
  • DOI: 10.7566/jpscp.3.011006
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Coexistence and Competition of Magnetic and Charge Orders in an Extended Kondo Lattice Model for Sm Skutterudite (2014)
  • Author(s): Ryousuke Shiina
  • Journal Title: J. Phys. Soc. Jpn. Volume: 83 Issue: 9 Pages: 094706-094706
  • DOI: 10.7566/jpsj.83.094706
  • NAID: 40020194624
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Effect of Magnetic Field on Spin Excitations in the Kondo Lattice Antiferromagnet (2014)
  • Author(s): Ryousuke Shiina
  • Journal Title: J. Phys. Soc. Jpn. Volume: 83 Issue: 12 Pages: 124705-124705
  • DOI: 10.7566/jpsj.83.124705
  • NAID: 40020299859
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Order Having Disorder in a New Samarium Compound (2014)
  • Author(s): Ryousuke Shiina
  • Journal Title: J. Phys. Soc. Jpn. News Comments Volume: 11 Pages: 15-15
  • DOI: 10.7566/jpsjnc.11.15
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Spin-Nematic Interaction in the Multiferroic Compound Ba2CoGe2O7 (2014)
  • Author(s): M. Soda, M. Matsumoto, M. Mansson, S. Ohira-Kawamura, K. Nakajima, R. Shiina, and T. Masuda
  • Journal Title: Phys. Rev. Lett Volume: Vol. 112 Issue: 12 Pages: 127205-127205
  • DOI: 10.1103/physrevlett.112.127205
  • Peer Reviewed
• [Journal Article] Theory of Metal-Insulator Transition and Unconventional Magnetic Ordering in SmRu4P12 (2013)
  • Author(s): R. Shiina
  • Journal Title: Journal of the Physical Society of Japan Volume: 82 Issue: 8 Pages: 083713-083713
  • DOI: 10.7566/jpsj.82.083713
  • NAID: 210000132686
  • Peer Reviewed
• [Presentation] Smスクッテルダイトの磁性電荷共存相における半金属状態と輸送特性 (2016)
  • Author(s): 椎名亮輔
  • Organizer: 日本物理学会
  • Place of Presentation: 東北学院大
  • Year and Date: 2016-03-16
• [Presentation] f 電子系における多極子秩序、揺らぎ、超伝導 (2014)
  • Author(s): 椎名亮輔
  • Organizer: 第13回CROSSroads 強相関電子系の物理
  • Place of Presentation: いばらき量子ビーム研究センター
  • Year and Date: 2014-12-02 – 2014-12-03
• [Presentation] Smスクッテルダイトの磁気・電荷複合秩序状態の理論 (2014)
  • Author(s): 椎名亮輔
  • Organizer: 研究会 特異な結晶構造に創出する新奇量子相の解明
  • Place of Presentation: 首都大学東京
  • Year and Date: 2014-09-26
• [Presentation] YbCo2Zn20における四極子相互作用と磁場誘起秩序 (2014)
  • Author(s): 椎名亮輔、金子耕士
  • Organizer: 日本物理学会
  • Place of Presentation: 中部大学
  • Year and Date: 2014-09-07 – 2014-09-10
• [Presentation] Smスクッテルダイトにおけるpf混成による競合的相互作用と高磁場相図 (2014)
  • Author(s): 椎名亮輔
  • Organizer: 日本物理学会
  • Place of Presentation: 東海大学，平塚
• [Presentation] p-f Mixing, Competing Interactions, and Unconventional Magnetism in SmRu4P12 (2013)
  • Author(s): R. Shiina
  • Organizer: International Conference on Strongly Correlated Electron System
  • Place of Presentation: The University of Tokyo