Details of the Researcher

PHOTO

Fumiya Hori
Section
Graduate School of Science
Job title
Assistant Professor
Degree

  • Ph.D. (Science) (Kyoto University)

e-Rad No.
41021900
Researcher ID
LDF-0397-2024

Research History 3

  • 2025/04 - Present
    Tohoku University　Graduate School of Science　Assistant Professor

  • 2023/04 - 2025/03
    Japan Society for the Promotion of Science　Research Fellowships for Young Scientists(DC2)

  • 2022/04 - 2023/03
    Kyoto University　Advanced Quantum Technology Fellowship to Create the Future

Research Interests 3

  • Superconductivity

  • Magnetism

  • Strongly correlated electron systems

Research Areas 1

  • Natural sciences / Magnetism, superconductivity, and strongly correlated systems /

Awards 6

  1. Best Poster Award

    2024/07　International Conference on Magnetism 2024

  2. Excellent Poster Award

    2024/05　「Unveiling, Design, and Development of Asymmetric Quantum Matters」FY2024 Area General Meeting/Public Research Kickoff Meeting

  3. Student Presentation Award of the Physical Society of Japan (Division 8)

    2024/03　Physical Society of Japan (JPSJ) 2024 Spring Meeting

  4. Special Researcher Award

    2023/09　The SATOMI Scholarship Foundation

  5. Excellent Poster Award

    2023/06　「Unveiling, Design, and Development of Asymmetric Quantum Matters」 kick-off meeting

  6. Bronze Award For the Best Poster Presentation

    2021/12　Oxide Superspin 2021 workshop

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Papers 15

  1. 「多極子カードゲーム」の開発 Peer-reviewed

    文哉 堀, 俊作 北川

    日本物理学会誌　2026/09/05

    DOI： 10.11316/butsuri.81.9_516 　

    ISSN： 0029-0181 2423-8872

  2. Sharp Structural and Magnetic Phase Transitions in High-Entropy Oxide (Mg0.2Mn0.2Co0.2Ni0.2Zn0.2)VO3 Peer-reviewed

    Hajime Yamamoto, Akira Hosono, Koki Matsushima, Fumiya Hori, Teppei Ichinose, Kenya Ohgushi, Takafumi Yamamoto, Tadashi Abukawa

    Inorganic Chemistry　65　(35)　20342-20347　2026/08/26

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.inorgchem.6c02659 　

    ISSN： 0020-1669

    eISSN： 1520-510X

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    Abstract Phase transitions in solid solutions generally tend to be broadened and diffused, often accompanied by the emergence of disordered phases. In this study, we report a contrasting result in a novel high-entropy compound, ilmenite-type (Mg0.2Mn0.2Co0.2Ni0.2Zn0.2)VO3, which exhibits a sharp structural phase transition accompanied by V–V dimerization, as well as an antiferromagnetic transition. (Mg0.2Mn0.2Co0.2Ni0.2Zn0.2)VO3 was obtained through high-pressure synthesis at 8 GPa and 1373 K for 1 h. At room temperature, the compound exhibited a triclinic ilmenite-type structure associated with V–V dimerization. Synchrotron X-ray diffraction (SXRD) and differential scanning calorimetry (DSC) measurements revealed that this compound underwent a structural transition to a rhombohedral phase at 510 K, concomitant with the disappearance of the V–V dimer structure. Furthermore, an antiferromagnetic transition was observed at 80 K through magnetic susceptibility and heat capacity measurements. The emergence of sharp structural and magnetic phase transitions, despite the high-entropy composition, represents a particularly noteworthy finding of this study.

  3. ジグザグ鎖構造をもつフラストレート磁性体YbCuS2の基底状態と準粒子励起 Peer-reviewed

    堀 文哉, 北川 俊作, 石田 憲二, 鬼丸孝博

    固体物理　61　(726)　411-420　2026/08

  4. Microscopic signatures of an imaginary charge density wave in a kagome metal Peer-reviewed

    S. Suetsugu, F. Hori, M. Shibata, S. Kitagawa, K. Ishida, T. Asaba, S. Nakazawa, Q. Li, H. -H. Wen, T. Shibauchi, H. Kontani, Y. Matsuda

    Nature Physics　2026/08

    DOI： 10.1038/s41567-026-03339-8 　

  5. Microscopic Determination of the c-axis-Oriented Antiferromagnetic Structure in LaMnSi by 55Mn and 139La NMR Peer-reviewed

    Yusuke Sakai, Fumiya Hori, Hiroki Matsumura, Shumpei Oguchi, Shunsaku Kitagawa, Kenji Ishida, Hiroshi Tanida

    Journal of the Physical Society of Japan　2026/02/15

    DOI： 10.7566/JPSJ.95.024702 　

  6. Antiferromagnetic Order and Magnetic Frustration in the Honeycomb Heavy-Fermion System Ce(Pt1−xPdx)6Al3: 27Al and 195Pt NMR Studies Peer-reviewed

    Shunsaku Kitagawa, Fumiya Hori, Kenji Ishida, Ryohei Oishi, Yasuyuki Shimura, Takahiro Onimaru, Toshiro Takabatake

    Journal of the Physical Society of Japan　2025/09/15

    DOI： 10.7566/JPSJ.94.094702 　

  7. Lu/Se Substitution Effect on Magnetic Properties of Yb-Based Zigzag Chain Semiconductor YbCuS2 Peer-reviewed

    Fumiya Hori, Hiroyasu Matsudaira, Shunsaku Kitagawa, Kenji Ishida, Souichiro Mizutani, Hirotaka Shirai, Takahiro Onimaru

    Physical Review B　2025/08/07

    DOI： 10.1103/bypl-fd1q 　

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    We have investigated the changes in the magnetic properties on YbCuS2 by Lu or Se substitutions from a microscopic perspective. In general, it is expected that nonmagnetic Lu substitution dilutes the magnetic Yb3+ concentration, and that Se substitution induces the negative pressure in YbCuS2. The 63/65Cu-nuclear quadrupole resonance (NQR) measurements on polycrystalline Yb0.9Lu0.1CuS2 and YbCu(S0.9Se0.1)2 revealed that the Se substitution leads to larger lattice expansion compared to the Lu substitution. The antiferromagnetic transition temperature TN decreased from 0.95 K in the unsubstituted system to 0.75 K in both substituted systems. Furthermore, the T-linear behavior of the 63Cu-NQR spin-lattice relaxation rate 1/T1, suggesting the presence of the gapless quasiparticle excitations, was observed even in the substituted systems, and the value of 1/T1T increases. These results under the chemical substitutions are opposite to those under pressure as previously reported, and are consistent with the expectation. Our systematic study indicates a clear relationship between the magnetic ordered states and the quasiparticle excitations in YbCuS2.

  8. Pressure Evolution of Magnetic Structure and Quasiparticle Excitations in Anisotropic Frustrated Zigzag Chains Peer-reviewed

    Fumiya Hori, Hiroyasu Matsudaira, Shunsaku Kitagawa, Kenji Ishida, Hiroto Suzuki, Takahiro Onimaru

    Communications Materials　2025/08/01

    DOI： 10.1038/s43246-025-00888-y 　

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    Frustrated magnetic systems with anisotropic exchange interactions have been recognized as key platforms for discovering exotic quantum states and quasiparticles. In this study, we report the pressure evolution of magnetic structures and quasiparticle excitations in the frustrated semiconductor YbCuS2, characterized by Yb3+ zigzag chains with competing exchange interactions. At ambient pressure, YbCuS2 exhibits a magnetic transition at TN ~ 0.95 K, forming an incommensurate helical magnetic order. Under hydrostatic pressure of 1.6 GPa, TN increases to 1.17 K, and the magnetic structure changes to a commensurate one, which can be regarded as an odd-parity magnetic multipole order. Remarkably, pressure suppresses the gapless quasiparticle excitations. These findings suggest that pressure alters the exchange interactions between the Yb ions, affecting both the magnetic ground state and the quasiparticle excitations. Our results highlight the pivotal role of anisotropic interactions in one-dimensionality to stabilize the complex quantum phases, offering insights into the interplay among frustration, dimensionality, multipoles and emergent quasiparticles.

  9. <Research Reports>Charge-neutral quasiparticles in a frustrated rare-earth compound YbCuS₂ Peer-reviewed

    Hori Fumiya, Kitagawa Shunsaku, Ishida Kenji

    45　3-12　2025/06

    Publisher:

    DOI： 10.14989/295494 　

    ISSN： 2758-1500

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    We have investigated the ground state and the quasiparticle excitations of the frustrated semiconductor YbCuS₂, where Yb forms zigzag chains with competing interactions. Analysis of the ⁶³ᐟ⁶⁵Cu-NQR spectrum reveals the antiferromagnetic phase transition at T_N ～0.95 K and the incommensurate magnetic structure. The ordered moment is significantly smaller than that expected from the crystalline electric field ground state, indicating the influence of frustration. Notably, the nuclear spin-lattice relaxation rate 1/T₁ is proportional to temperature below 0.5 K, suggesting the emergence of gapless charge-neutral quasiparticle excitations in the antiferromagnetic ordered state of YbCuS₂. In addition, such gapless excitations are modified by applying pressure and chemical substitutions. Our findings highlight the critical role of the frustration effect with the anisotropy in the emergence of exotic quantum phenomena in this system.

  10. Magnetic-Field Dependence of Paramagnetic Properties Investigated by 63/65Cu-NMR on the Yb Zigzag-Chain Semiconductor YbCuS2 Peer-reviewed

    Fumiya Hori, Shunsaku Kitagawa, Kenji Ishida, Yudai Ohmagari, Takahiro Onimaru

    Journal of the Physical Society of Japan　2025/02/15

    DOI： 10.7566/JPSJ.94.024706 　

  11. Gapped Spin Excitation in Magnetic Ordered State on Yb-Based Zigzag Chain Compound YbAgSe2 Peer-reviewed

    Fumiya Hori, Shunsaku Kitagawa, Kenji Ishida, Souichiro Mizutani, Yudai Ohmagari, Takahiro Onimaru

    Journal of the Physical Society of Japan　2024/11/15

    DOI： 10.7566/JPSJ.93.114702 　

  12. Superconducting spin reorientation in spin-triplet multiple superconducting phases of UTe 2 Peer-reviewed

    Katsuki Kinjo, Hiroki Fujibayashi, Hiroki Matsumura, Fumiya Hori, Shunsaku Kitagawa, Kenji Ishida, Yo Tokunaga, Hironori Sakai, Shinsaku Kambe, Ai Nakamura, Yusei Shimizu, Yoshiya Homma, Dexin Li, Fuminori Honda, Dai Aoki

    Science Advances　2023/07/28

    DOI： 10.1126/sciadv.adg2736 　

  13. Gapless fermionic excitation in the antiferromagnetic state of ytterbium zigzag chain Peer-reviewed

    Fumiya Hori, Katsuki Kinjo, Shunsaku Kitagawa, Kenji Ishida, Souichiro Mizutani, Rikako Yamamoto, Yudai Ohmagari, Takahiro Onimaru

    Communications Materials　2023/07/21

    DOI： 10.1038/s43246-023-00381-4 　

  14. Enhancement of charge-neutral fermionic excitations near the spin-flop transition in the magnetic Kondo material YbIr3Si7 Peer-reviewed

    Shunsaku Kitagawa, Takumi Kobayashi, Fumiya Hori, Kenji ISHIDA, Andriy H. Nevidomskyy, Long Qian, Emilia Morosan

    Physical Review B　106　(10)　2022/09/16

    Publisher: American Physical Society ({APS})

    DOI： 10.1103/physrevb.106.l100405 　

    ISSN： 2469-9950 2469-9969

  15. Impurity-Robust Bulk Gapless Excitation in the Yb-Based Zigzag Chain Compound YbCuS2 Peer-reviewed

    Fumiya Hori, Katsuki Kinjo, Shunksaku Kitagawa, Kenji Ishida, Yudai Ohmagari, Takahiro Onimaru

    Journal of Physics: Conference Series　2164　(1)　012027-012027　2022/03/01

    Publisher: {IOP} Publishing

    DOI： 10.1088/1742-6596/2164/1/012027 　

    ISSN： 1742-6588 1742-6596

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    <jats:title>Abstract</jats:title> <jats:p>We have performed <jats:sup>63</jats:sup>Cu-nuclear quadrupole resonance (NQR) measurements using a lump sample of the Yb zigzag-chain compound YbCuS<jats:sub>2</jats:sub> with a small surface area to investigate the sample dependence of low-temperature magnetic properties in YbCuS<jats:sub>2</jats:sub> by comparing with the previous study with different powdered sample. The line width of NQR signals in the present lump sample is larger than that in the previous powdered sample. In addition, the transition temperature <jats:italic>T</jats:italic> <jats:sub>N</jats:sub> ∼ 0.92 K in the present lump sample is lower than that in the previous powdered sample (∼ 0.95 K). These results suggest that the quality of the present lump sample is worse than that of the previous powdered sample. However, the <jats:italic>T</jats:italic>-linear behavior of the nuclear spin-lattice relaxation rate 1/T<jats:sub>1</jats:sub> was observed below 0.5 K and the value of 1/<jats:italic>T</jats:italic> <jats:sub>1</jats:sub> <jats:italic>T</jats:italic> in both samples is almost the same even though the sample quality and sample geometry are different. This suggests that <jats:italic>T</jats:italic>-linear behavior in 1/<jats:italic>T</jats:italic> <jats:sub>1</jats:sub> arises from the impurity-robust bulk gapless excitation inherent in YbCuS<jats:sub>2</jats:sub> rather than from sample issues such as the sample quality or geometry.</jats:p>

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Presentations 12

  1. Field-Induced Strain in the Tsai-Type Magnetic Quasicrystal Au56In28.5Eu15.5

    F. Hori, H. Nanjo, T. Taniguchi, Y. Imai, F. Labib, R. Tamura, K. Ohgushi

    International Conference on Strongly Correlated Electron Systems 2026 (SCES 2026)　2026/09/30

  2. Verification of the Piezomagnetic Effect in the Tsai-Type Magnetic Quasicrystal Au56In28.5Eu15.5

    F. Hori, H. Nanjo, T. Taniguchi, Y. Imai, F. Labib, R. Tamura, K. Ohgushi

    International Conference on Asymmetric Quantum Matters (Asymmetry 2026)　2026/09/24

  3. Pressure Evolution of Magnetic Structures and Quasiparticle Excitations in the Frustrated Zigzag-Chain Compound YbCuS2

    Fumiya Hori, Hiroyasu Matsudaira, Shunsaku Kitagawa, Kenji Ishida, Souichiro Mizutani, Hirotaka Shirai, Hiroto Suzuki, Takahiro Onimaru

    International Conference on Strongly Correlated Electron Systems 2025, Montréal, Canada　2025/07/07

  4. Emergent charge-neutral quasiparticle in the 4f antiferromagnetic zigzag chain Invited

    Fumiya Hori

    KUJI QMAT Seminar #42, Cambridge, Kyoto, Seoul, and Salerno; Online　2024/08/22

  5. Evolution of Magnetic Properties in Yb Zigzag Chain Semiconductor YbCuS2 under Varied Conditions: Substitution, Pressure, and Magnetic Field

    F. Hori, H. Matsudaira, S. Kitagawa, K. Ishida, H. Shirai, S. Mizutani, H. Suzuki, Y. Ohmagari, T. Onimaru

    International Conference on Magnetis;IC;Bologna, Italy　2024/07/02

  6. Charge-neutral quasiparticles in a 4f zigzag-chain semiconductor YbCuS2

    Fumiya Hori

    H-Physics Workshop: Topology, spin-orbit interactions and superconductivity in strongly correlated quantum materials under extreme conditions, Grenoble, France　2023/10/11

  7. Lu, Se substitution effect on ordered state and magnetic excitation in a Yb zigzag chain semiconductor YbCuS2

    F. Hori, S. Kitagawa, K. Ishida, H. Shirai, S. Mizutani, T. Onimaru

    International Conference on Strongly Correlated Electron Systems 2023 (SCES 2023), Incheon, Korea　2023/07/05

  8. Metallic-like Excitation in the Antiferromagnetic State of a Yb Zigzag Chain Semiconductor

    Fumiya Hori

    International Symposium on Creation of Advanced Photonic and Electronic Devices 2023 / International Symposium on Advanced Quantum Technology for Future 2023, Kyoto, Japan　2022/09/30

  9. Magnetic ground state in semiconducting Yb-based compounds with a zigzag-chain structure

    F. Hori, K. Kinjo, S. Kitagawa, K. Ishida, S. Mizutani, Y. Ohmagari, T. Onimaru

    International Conference on Strongly Correlated Electron Systems 2022, Amsterdam, The Netherlands　2022/07/24

  10. Metallic-like excitation in the frustrated semiconductor YbCuS2

    F. Hori, K. Kinjo, S. Kitagawa, K. Ishida, Y. Ohmagari, T. Onimaru

    Oxide Superspin 2021 workshop, Kyoto, Japan　2021/12/13

  11. Unkown Gapless Excitation in Antiferromagnetic State of Yb Zigzag Chain System YbCuS2

    F. Hori, K. Kinjo, S. Kitagawa, K. Ishida, Y. Ohmagari, T. Onimaru

    nternational Conference on Strongly Correlated Electrons Systems 2020, São Paulo, Brazil; Online　2021/09/27

  12. Low-temperature magnetic state in Yb-based semiconductors with a zigzag-chain structure

    Fumiya Hori

    nternational Seminar Dojo 2022 / Workshop for Advanced Quantum Technology for Future 2022, Kyoto, Japan

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Research Projects 6

  1. 非周期性をもつ準結晶に潜在する高次磁気多極子の検出

    堀 文哉

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 研究活動スタート支援

    Institution: 東北大学

    2025/07/31 - 2027/03/31

  2. ⾦属磁性体の新物質開発と新奇量⼦相の開拓

    Offer Organization: Tohoku University

    System: 若手研究者アンサンブルグラント

    2025/06 - 2026/03

  3. Pressure Evolution of Magnetic Structures and Quasiparticle Excitations in the Frustrated Zigzag-Chain Compound YbCuS2

    Offer Organization: 湯川記念財団「望月基金」

    2025/07 -

  4. フラストレーションを内在する希土類化合物に見られた中性フェルミオンの解明

    堀 文哉

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 特別研究員奨励費

    Institution: 京都大学

    2023/04/25 - 2025/03/31

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    （１）YbCuS2で観測された新奇な秩序状態、準粒子励起の起源や性質を調べるため、圧力効果および元素置換効果を調べた。約1 GPaの圧力下で、転移温度TN ~ 1.05 Kと常圧のTN ~ 0.95 Kの値に比べて上昇するのに対し、Lu、Seで10%置換したYb0.9Lu0.1CuS2、YbCu(S0.9Se0.1)2については、いずれもTN ~ 0.75 Kと無置換系のTNの値に比べて減少した。一方で、低温の核スピン-格子緩和率1/T1の値を比較すると、圧力効果で減少し、元素置換効果で上昇する。これらの結果をまとめると、圧力と元素置換は相反する効果を持ち、TNと1/T1の値が系統的に変化していることがわかった。TN以下の秩序状態は鎖間相互作用を起源としており、低温で見られる中性準粒子は、最近、理論提案された異方的相互作用をもつジグザグ鎖スピン系モデルで発現するネマティック粒子に関連していると考えられる。これらの成果については日本物理学会で報告し、現在、論文執筆中である。 <BR> （２）YbCuS2で観測された中性準粒子がYbジグザグ鎖のフラストレーションに由来した普遍的な現象であるのかどうか調べるため、YbCuS2と同型構造をもち、格子定数の異なるYbAgSe2に対してSe核の核磁気共鳴（NMR）測定を行った。YbAgSe2のナイトシフトは、高温域では磁化率にスケールする一方で、TN ~ 1.8 K以下で磁化率とのスケールは破れる。また同じ温度から1/T1が急激に減少し、指数関数的に減衰することから、マグノンギャップをもつ磁気秩序状態であることが分かった。YbCuS2で観測されたギャップレスな準粒子励起の挙動は1.0 Kまで観測されなかった。この成果については、Journal of the Physical Society of Japanに投稿予定である。

  5. フラストレーションを内在する希土類磁性化合物における新奇現象の探索

    Offer Organization: 京都大学

    System: 「未来を創る先端量子技術フェローシップ」研究費

    2022/05 - 2023/03

  6. 希土類ジグザグ鎖における新奇磁気励起の解明

    Offer Organization: 京都大学

    System: 「未来を創る先端量子技術フェローシップ」インターンシップ補助金

    2022/10 -

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Teaching Experience 4

  1. 「物理学実験I」課題2「電磁誘導」　Tohoku University

  2. 「自然科学総合実験」課題9「弦の振動と音楽」　Tohoku University

  3. 「物理学実験I」課題2「電磁誘導」　Tohoku University

  4. 「自然科学総合実験」課題7「光のスペクトル」　Tohoku University