Publications

2025年

・ Systematic evolution of superconducting pairing strength and Seebeck coefficients in correlated infinite-layer La1-xSrxNiO2

M. Osada, S. Imajo, Y. Seki, K. Ishida, T. Nojima, K. Fujiwara, K. Kindo, Y. Nomura, and A. Tsukazaki

Sci. Adv. 11, eadv6488 (2025).

・ Electronic Structure of Kramers Nodal-Line Semimetal YAuGe and Anomalous Hall Effect Induced by Magnetic Rare-Earth Substitution

T. Kurumaji, J. I. Facio, N. Mitsuishi, S. Imajo, M. Gen, M. Kimata, L. Ye, D. Graf, M. Sakano, M. Kitamura, K. Yamagami, K. Ishizaka, K. Kindo, and T. Arima

Adv. Sci. 12, 2501669 (2025).

・ Zero-field Hall effect emerging from a non-Fermi liquid in a collinear antiferromagnet V1/3NbS2

M. K. Ray, M. Fu, Y. Chen, T. Chen, T. Nomoto, S. Sakai, M. Kitatani, M. Hirayama, S. Imajo, T. Tomita, A. Sakai, D. Nishio-Hamane, G. T. McCandless, M. Suzuki, Z. Xu, Y. Zhao, T. Fennell, Y. Kohama, J. Y. Chan, R. Arita, C. Broholm, and S. Nakatsuji

Nat. Commun. 16, 3532 (2025).

プレスリリース：共線反強磁性異常金属におけるゼロ磁場異常ホール効果の発見

・ Radical-cation salts of BEDT-TTF with tris-coordinated racemic dysprosium(III) and terbium(III) anions

E. Howarth, J. Lopez, J. O. Ogar, T. J. Blundell, H. Akutsu, Y. Nakazawa, S. Imajo, Y. Ihara, S. J. Coles, P. N. Horton, J. Christensen, and L. Martin

Dalton Trans. 54, 3207 (2025). 

・ Spontaneous Resolution of the Fe(C2O4)3 Anion and Inclusion of Chiral Guest Molecules in BEDT-TTF Radical-Cation Salts

J. O. Ogar, J. D. Wallis, T. J. Blundell, E. K. Rusbridge, A. Mantle, H. Akutsu, Y. Nakazawa, S. Imajo, and L. Martin

Inorg. Chem. 64, 1075 (2025).

・ Frustrated Magnetism in a Gyroidal Metal–Organic Framework Magnet

S. Imajo, H. Ishikawa, K. Kindo, K. Nakashima, R. Suizu, and K. Awaga

Chem. Mater. 37, 297 (2025).

2024年

・Suppression of a structural phase transition by an orientational disorder of counter anions in an organic conductor,  β″-β″-(BEDT-TTF)2ClC2H4SO3

H. Akutsu, M. Uruichi, S. Imajo, K. Kindo, T. Masuta, H. Manabe, Y. Nakazawa, and S. S. Turner

Inorg. Chem. 63, 16872 (2024). 

・ Evidence for large thermodynamic signatures of in-gap fermionic quasiparticle states in a Kondo insulator

Z. Yang, C. Marcenat, S. Kim, S. Imajo, M. Kimata, T. Nomura, A. D. Muer, D. K. Maude, F. Iga, T. Klein, D. Chowdhury, and Y. Kohama

Nat. Commun. 15, 7801 (2024).

プレスリリース：磁場下で電荷を持たない新粒子を観測 ―熱測定により、電荷中性の新粒子の量子化現象を発見―

・ BEDT-TTF radical-cation salts with tris(oxalato)chromate and guest additives

T. J. Blundell, J. Ogar, M. J. Brannan, E. K. Rusbridge, J. D. Wallis, H. Akutsu, Y. Nakazawa, S. Imajo, and L. Martin

RCS Advances 14, 18444 (2024).

・Magnetic-field-induced insulator-to-metal Mott transition in λ-type organic conductors

S. Fukuoka, T. Oka, Y. Ihara, A. Kawamoto, S. Imajo, and K. Kindo

Phys. Rev. B 109, 195142 (2024).

・ Magnetic anisotropy of CeCoSi under high magnetic field

T. Kanda, H. Ishikawa, S. Imajo, K. Kindo, H. Tanida, and Y. Kohama

Phys. Rev. B 109, 174402 (2024).

・ Jeff = 1/2 hyperoctagon lattice in cobalt oxalate metal-organic-framework

H. Ishikawa, S. Imajo, H. Takeda, M. Kakegawa, M. Yamashita, J. Yamaura, and K. Kindo

Phys. Rev. Lett. 132, 156702 (2024).

プレスリリース：MOFのハイパーオクタゴン格子でゆらぐスピン ―量子計算の舞台となる物質の開発を次の次元へ―

・ Introduction of new guest molecules into BEDT-TTF radical-cation salts with tris(oxalato)ferrate

T. J. Blundell, E. K. Rusbridge, R. E. Pemberton, M. J. Brannan, A. L. Morritt, J. Ogar, J. D. Wallis, H. Akutsu, Y. Nakazawa, S. Imajo, and L. Martin

CrystEngComm 26, 1962-1975 (2024).

・ Quantum liquid states of spin solitons in a ferroelectric spin-Peierls state

S. Imajo, A. Miyake, R. Kurihara, M. Tokunaga, K. Kindo, S. Horiuchi, and F. Kagawa

Phys. Rev. Lett. 132, 096601 (2024).

2023年

・ Pseudogap formation in organic superconductors

S. Imajo, T. Kobayashi, Y. Matsumura, T. Maeda, Y. Nakazawa, H. Taniguchi, and K. Kindo

Phys. Rev. Materials 7, 124803 (2023).

・ Insights into Thermal Transport through Molecular π-Stacking

R. Takehara, N. Kubo, M. Ryu, S. Kitani, S. Imajo, Y. Shoji, H. Kawaji, J. Morikawa, and T. Fukushima

J. Am. Chem. Soc. 145, 22115 (2023).

・  Expanded quantum vortex liquid regime in the electron nematic superconductors FeSe1-xSx and FeSe1-xTex

M. Čulo, S. Licciardello, K. Ishida, K. Mukasa, S. Imajo, M. W. Qiu, M. Saito, Y. Uezono, T. Otsuka, T. Watanabe, K. Kindo, J. Ayres, J. Buhot, Y.-T. Hsu, T. Shibauchi, S. Kasahara, Y. Matsuda, and N. E. Hussey

Nat. Commun. 14, 4150 (2023).

・  Superconductivity at 12 K in La2IOs2: A 5d metal with osmium honeycomb layer

H. Ishikawa, T. Yajima, D. Nishio-Hamane, S. Imajo, K. Kindo, and M. Kawamura

Phys. Rev. Materials 7, 054804 (2023).

・ Quantum oscillations in a centrosymmetric skyrmion-hosting magnet GdRu2Si2

N. Matsuyama, T. Nomura, S. Imajo, T. Nomoto, R. Arita, K. Sudo, M. Kimata, N. D. Khanh, R. Takagi, Y. Tokura, S. Seki, K. Kindo, and Y. Kohama

Phys. Rev. B 107, 104421 (2023). Editors’ Suggestion

・ Enhanced superconducting pairing strength near a pure nematic quantum critical point

K. Mukasa, K. Ishida, S. Imajo, M. W. Qiu, M. Saito, K. Matsuura, Y. Sugimura, S. Liu, Y. Uezono, T. Otsuka, M. Čulo, S. Kasahara, Y. Matsuda, N. E. Hussey, T. Watanabe, K. Kindo, and T. Shibauchi

Phys. Rev. X 13, 011032 (2023).

プレスリリース：超伝導の新しいメカニズム 「量子液晶揺らぎによる電子対形成」の検証に成功

 ・ Correlation-driven organic 3D topological insulator with relativistic fermions

T. Nomoto, S. Imajo, H. Akutsu, Y. Nakazawa, and Y. Kohama

Nat. Commun. 14, 2130 (2023).

プレスリリース：有機物質で初めてのトポロジカル絶縁体を発見 ―外場制御の容易な新しい有機エレクトロニクス材料の開拓へ

・ Thermodynamic properties of the Mott insulator-metal transition in a triangular lattice system without magnetic order

E. Yesil, S. Imajo, S. Yamashita, H. Akutsu, Y. Saito, A. Pustogow, A. Kawamoto, and Y. Nakazawa

Phys. Rev. B 107, 045133 (2023).

2022年

・ Magnetically hidden state on the ground floor of the magnetic devil’s staircase

S. Imajo, N. Matsuyama, T. Nomura, T. Kihara, S. Nakamura, C. Marcenat, T. Klein, G. Seyfarth, C. Zhong, H. Kageyama, K. Kindo, T. Momoi, and Y. Kohama

Phys. Rev. Lett. 129, 147201 (2022).

物性研ニュース：「磁気的な悪魔の階段」の手前に「隠れた状態」を発見

・ Emergent anisotropy in the Fulde–Ferrell–Larkin–Ovchinnikov state

S. Imajo, T. Nomura, Y. Kohama, and K. Kindo

Nat. Commun. 13, 5590 (2022). Editor's Highlights "Condensed matter"

プレスリリース：強磁場中でも生き残る空間的に変調した超伝導を有機物中で発見

・ Role of the anion layer's polarity in organic conductors β″-(BEDT-TTF)2XC2H4SO3 (X = Cl and Br)

H. Akutsu, M. Uruichi, S. Imajo, K. Kindo, Y. Nakazawa, and S. Turner

J. Phys. Chem. C 126, 16529 (2022).

・ Superconductivity and charge ordering in BEDT-TTF based organic conductors with β″-type molecular arrangement

Y. Ihara and S. Imajo

Crystals 12, 711 (2022).

・ Molecular conductors from bis(ethylenedithio)tetrathiafulvalene with tris(oxalato)gallate and tris(oxalato)iridate

T. J. Blundell, A. L. Morritt, E. K. Rusbridge, L. Quibell, J. Oakes, H. Akutsu, Y. Nakazawa, S. Imajo, T. Kadoya, J. Yamada, S. J. Coles, J. Christensene, and L. Martin

Mater. Adv. 3, 4724 (2022).

・ Quantum phase of the chromium spinel oxide HgCr2O4 in high magnetic fields

S. Kimura, S. Imajo, M. Gen, T. Momoi, M. Hagiwara, H. Ueda, and Y. Kohama

Phys. Rev. B 105, L180405 (2022).

・ Band-filling Effects in Single-crystalline Oligomer Models for Doped PEDOT: 3,4-Ethylenedioxythiophene (EDOT) Dimer Salt with Hydrogen-bonded Infinite Sulfate Anion Chains

R. Kameyama, T. Fujino, S. Dekura, S. Imajo, T. Miyamoto, H. Okamoto, and H. Mori

J. Mater. Chem. C 10, 7543 (2022).

・ Persistence of fermionic spin excitations through a genuine Mott transition in κ-type organics

S. Imajo, N. Kato, R. J. Marckwardt, E. Yesil, H. Akutsu, and Y. Nakazawa

Phys. Rev. B 105, 125130 (2022).

・ Electronic Heat Capacity and Lattice Softening of Partially Deuterated Compounds of κ-(BEDT-TTF)2Cu[N(CN)2]Br

Y. Matsumura, S. Imajo, S. Yamashita, H. Akutsu, and Y. Nakazawa

Crystals 12, 2 (2022).

2021年

・ The FFLO State in the Dimer Mott Organic Superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br

S. Imajo and K. Kindo

Crystals 11, 1358 (2021).

・ Extraordinary π-Electron Superconductivity Emerging from a Quantum Spin Liquid

S. Imajo, S. Sugiura, H. Akutsu, Y. Kohama, T. Isono, T. Terashima, K. Kindo, S. Uji, and Y. Nakazawa

Phys. Rev. Research 3, 033026 (2021).

・ First molecular superconductor with the tris(oxalato)aluminate anion, β″-(BEDT-TTF)4(H3O)Al(C2O4)3C6H5Br, and isostructural tris(oxalato)cobaltate and -ruthenate radical-cation salts

T. J. Blundell, M. Brannan, J. M.-Newman, H. Akutsu, Y. Nakazawa, S. Imajo, L. Martin

Magnetochemistry 7, 90 (2021).

・ Normal state specific heat in the cuprate superconductors La2−xSrxCuO4 and Bi2+ySr2−x−yLaxCuO6+δ near the critical point of the pseudogap phase

C. Girod, D. LeBoeuf, A. Demuer, G. Seyfarth, S. Imajo, K. Kindo, Y. Kohama, M. Lizaire, A. Legros, A. Gourgout, H. Takagi, T. Kurosawa, M. Oda, N. Momono, J. Chang, S. Ono, G.-q. Zheng, C. Marcenat, L. Taillefer, and T. Klein

Phys. Rev. B 103, 214506 (2021).

・ Thermodynamic evidence for the formation of a Fulde-Ferrell-Larkin-Ovchinnikov phase in the organic superconductor λ-(BETS)2GaCl4

S. Imajo, T. Kobayashi, A. Kawamoto, K. Kindo, and Y. Nakazawa

Phys. Rev. B 103, L220501 (2021).

・ Quantum transport of topological spin solitons in a one-dimensional organic ferroelectric

S. Imajo, A. Miyake, R. Kurihara, M. Tokunaga, K. Kindo, S. Horiuchi, and F. Kagawa

Phys. Rev. B 103, L201117 (2021).

・  Revealing three-dimensional quantum criticality by Sr-substitution in Han Purple

S. Allenspach, P. Puphal, J. Link, I. Heinmaa, E. Pomjakushina, C. Krellner, J. Lass, G. S. Tucker, C. Niedermayer, S. Imajo, Y. Kohama, K. Kindo, S. Krämer, M. Horvatić, M. Jaime, A. Madsen, A. Mira, N. Laflorencie, F. Mila, B. Normand, C. Rüegg, R. Stern, and F. Weickert

Phys. Rev. Research 3, 023177 (2021).

・ High-resolution calorimetry in pulsed magnetic fields

S. Imajo, C. Dong, A. Matsuo, K. Kindo, and Y. Kohama

Rev. Sci. Instrum. 92, 043901 (2021).

・ Symmetry change of d-wave superconductivity in κ-type organic superconductors

S. Imajo, K. Kindo, and Y. Nakazawa

Phys. Rev. B 103, L060508 (2021).

2020年

・ Thermal and magnetoelastic properties of α-RuCl3 in the field-induced low-temperature states

R. Schönemann, S. Imajo, F. Weickert, J. Yan, D. G. Mandrus, Y. Takano, E. L. Brosha, P. F. S. Rosa, S. E. Nagler, K. Kindo, M. Jaime

Phys. Rev. B 102, 214432 (2020).

・ Anisotropic Fully Gapped Superconductivity Possibly Mediated by Charge Fluctuations in a Nondimeric Organic Complex

S. Imajo, H. Akutsu, R. Kurihara, T. Yajima, Y. Kohama, M. Tokunaga, K. Kindo, and Y. Nakazawa

Phys. Rev. Lett. 125, 177002 (2020).

・ Variation of Electronic Heat Capacity of κ-(BEDT-TTF)2Cu[N(CN)2]Br Induced by Partial Substitution of Donor Layers

E. Yesil, S. Imajo, T. Nomoto, S. Yamashita, H. Akutsu, and Y. Nakazawa

J. Phys. Soc. Jpn. 89, 073701 (2020).

・ Electronic band structure of (111) SrRuO3 thin films: An angle-resolved photoemission spectroscopy study

H. Ryu, Y. Ishida, B. Kim, J. R. Kim, W. J. Kim, Y. Kohama, S. Imajo, Z. Yang, W. Kyung, S. Hahn, B. Sohn, I. Song, M. Kim, S. Huh, J. Jung, D. Kim, T. W. Noh, S. Das, and C. Kim

Phys. Rev. B 102, 041102 (2020).

2019年

・ Effects of electron correlations and chemical pressures on superconductivity of β″-type organic compounds

S. Imajo, H. Akutsu, A. Akutsu-Sato, A. L. Morritt, L. Martin, and Y. Nakazawa

Phys. Rev. Research 1, 033184 (2019).

・ 2D Molecular Superconductor to Insulator Transition in the β″-(BEDT-TTF)2[(H2O)(NH4)2M(C2O4)3]　18-crown-6 Series (M = Rh, Cr, Ru, Ir)

A. L. Morritt, J. R. Lopez, T. J. Blundell, E. Canadell, H. Akutsu, Y. Nakazawa, S. Imajo, and L. Martin

Inorg. Chem. 58, 10656 (2019).

・ Thermodynamic Investigation of Metamagnetism in Pulsed High Magnetic Fields on Heavy Fermion Superconductor UTe2

S. Imajo, Y. Kohama, A. Miyake, C. Dong, M. Tokunaga, J. Flouquet, K. Kindo, and D. Aoki

J. Phys. Soc. Jpn. 88, 083705 (2019).

・ Gap Symmetry of the Organic Superconductor λ-(BETS)2GaCl4 Determined by Magnetic-Field-Angle-Resolved Heat Capacity

S. Imajo, S. Yamashita, H. Akutsu, H. Kumagai, T. Kobayashi, A. Kawamoto, and Y. Nakazawa

J. Phys. Soc. Jpn. 88, 023702 (2019).

・ Construction of a thermal conductivity measurement system for small single crystals of organic conductors

T. Nomoto, S. Imajo, S. Yamashita, H. Akutsu, Y. Nakazawa, and A. I. Krivchikov

J. Therm. Anal. Calorim. 135, 2831 (2019).

2018年

・ Superconducting Phase Diagram of the Organic Superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br above 30 T

S. Imajo, Y. Nakazawa, and K. Kindo

J. Phys. Soc. Jpn. 87, 123704 (2018).

・ Thermodynamic Picture of Dimer-Mott Organic Superconductors Revealed by Heat Capacity Measurements with External and Chemical Pressure Control

Y. Nakazawa, S. Imajo, Y. Matsumura, S. Yamashita, and H. Akutsu

Crystals 8, 143 (2018).

・  Development of Light Irradiation Calorimetry System for Molecule-based Compounds

Y. Matsumura, S. Kataoka, S. Imajo, S. Yamashita, H. Akutsu, and Y. Nakazawa

Int. J. Mod. Phys. B 32, 1840035 (2018).

・ Thermodynamic Investigation by Heat Capacity Measurements of κ-type Dimer-Mott Organic Compounds with Chemical Pressure Tuning

Y. Matsumura, S. Imajo, S. Yamashita, H. Akutsu, and Y. Nakazawa

Int. J. Mod. Phys. B 32, 1840024 (2018).

2017年

・ Bulk Kosterlitz-Thouless molecular superconductor β″-(BEDT-TTF)2[(H2O)(NH4)2Cr(C2O4)3] 18-crown-6

L. Martin, J. R. Lopez, H. Akutsu, Y. Nakazawa, and S. Imajo

Inorg. Chem. 56, 14045 (2017).

・ Molecular conductors from bis(ethylenedithio)tetrathiafulvalene with tris(oxalato)rhodate

L. Martin, A. L. Morritt, J. R. Lopez, Y. Nakazawa, H. Akutsu, S. Imajo, Y. Ihara, B. Zhang, and Y. Guo

Dalton Trans. 46, 9542 (2017).

・ AC Calorimetry System Using Commercially available Microchip Device and its Application for Tiny Single Crystals of Molecule-Based Compounds

M. Murase, S. Yamashita, R. Yoshimoto, S. Imajo, Y. Nakazawa, K. Ueda, and R. Kato

Thermochim. Acta. 650, 134 (2017).

・ Ambient-pressure molecular superconductor with a superlattice containing layers of tris(oxalato)rhodate enantiomers and 18-crown-6

L. Martin, A. L. Morritt, J. R. Lopez, H. Akutsu, Y. Nakazawa, S. Imajo, and Y. Ihara

Inorg. Chem. 56, 717 (2017).

2016年

・ Thermodynamic Evidence of d-wave Superconductivity of the Organic Superconductor λ-(BETS)2GaCl4

S. Imajo, N. Kanda, S. Yamashita, H. Akutsu, Y. Nakazawa, H. Kumagai, T. Kobayashi, and A. Kawamoto

J. Phys. Soc. Jpn. 85, 043705 (2016). Editors’ Choice

・ Quadratic Temperature Dependence of Electronic Heat Capacities in the κ-type Organic Superconductors

S. Imajo, S. Yamashita, H. Akutsu, and Y. Nakazawa

Int. J. Mod. Phys. B, 30, 1642014 (2016).

・ Thermal Anomaly around the Superconductive Transition of κ-(BEDT-TTF)2Cu(NCS)2 with External Pressure and Magnetic Field Control

Y. Muraoka, S. Imajo, S. Yamashita, H. Akutsu, and Y. Nakazawa

J. Therm. Anal. Calorim. 123, 1891 (2016).

・ Construction of relaxation calorimetry for 101–2 μg samples and heat capacity measurements of organic complexes

S. Imajo, S. Fukuoka, S. Yamashita, H. Akutsu, and Y. Nakazawa

J. Therm. Anal. Calorim. 123, 1871 (2016).

・「熱力学量から探る有機超伝導体の準粒子励起構造」

今城周作

「熱測定」熱測定学会　2025年4月号

・「有機超伝導体におけるFulde-Ferrell-Larkin-Ovchinnikov状態」

今城周作，杉浦栞理

「固体物理」アグネ技術センター　2023年6月号

・「分子性電荷移動塩の超伝導ギャップの構造と対称性の熱力学的解析」

今城周作，中澤康浩

「日本物理学会誌」日本物理学会　2023年2月号

・「FFLO超伝導が創る空間異方性」

今城周作

「物性研だより」東京大学物性研究所　2022年度第62巻 第4号

・「微小試料用高感度熱量計を用いた磁場角度回転熱容量測定による電子物性研究」

今城周作，福地宗太郎，中澤康浩

「熱測定」熱測定学会　2019年7月号

・「λ型構造をもつ有機超伝導体のギャップ構造の対称性」

今城周作，中澤康浩

「日本物理学会誌」 日本物理学会　2016年8月号

・「物質化学百問集」

編集委員長を担当 大阪大学出版会　初版　2018年2月

・2024年4月18日

共線反強磁性異常金属におけるゼロ磁場異常ホール効果の発見

Nature Communications 16, 3532 (2025).

・2024年9月12日

磁場下で電荷を持たない新粒子を観測 ―熱測定により、電荷中性の新粒子の量子化現象を発見―

Nature Communications  15, 7801 (2024).

・2024年4月12日

MOFのハイパーオクタゴン格子でゆらぐスピン ―量子計算の舞台となる物質の開発を次の次元へ―

Physical Review Letters 132, 156702 (2024).

・2023年6月2日

重いアニオン遷移金属ハニカム格子をもつ超伝導物質の発見

Physical Review Materials 7, 054804 (2023).

・2023年4月20日

有機物質で初めてのトポロジカル絶縁体を発見 ―外場制御の容易な新しい有機エレクトロニクス材料の開拓へ

Nature Communications 14, 2130 (2023).

・2023年3月9日

超伝導の新しいメカニズム 「量子液晶揺らぎによる電子対形成」の検証に成功

Physical Review X 13, 011032 (2023).

・2022年10月3日

「磁気的な悪魔の階段」の手前に「隠れた状態」を発見

Physical Review Letters 129, 147201 (2022).

・2022年10月3日

強磁場中でも生き残る空間的に変調した超伝導を有機物中で発見

Nature Communications 13, 5590 (2022).