Details of the Researcher

PHOTO

Yu Kumagai
Section
Institute for Materials Research
Job title
Professor
Degree

  • 博士（工学）（京都大学）

  • 修士（工学）（京都大学）

Research History 8

  • 2019/06 - 2022/03
    Tokyo Institute of Technology

  • 2018/12 - 2019/05
    Kyoto University　Graduate School of Engineering Deprtment of Materical Science and Engineering

  • 2016/12 - 2018/11
    Tokyo Institute of Technology　Materials Research Center for Element Strategy

  • 2015/09 - 2016/11
    Tokyo Institute of Technology　Materials Research Center for Element Strategy

  • 2012/12 - 2015/08
    Tokyo Institute of Technology　Materials Research Center for Element Strategy

  • 2011/04 - 2012/11
    Japan Society for the Promotion of Science

  • 2010/04 - 2011/03
    Kyoto University　Graduate School of Engineering

  • 2022/04 -
    Tohoku University　Institute for Materials Research

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Education 3

  • Kyoto University　大学院工学研究科　Deprtment of Materical Science and Engineering

    2007/04 - 2010/03

  • Kyoto University　Graduate School of Engineering　Deprtment of Materical Science and Engineering

    2005/04 - 2007/03

  • Kyoto University　Faculty of Engineering　School of Global Engineering

    2001/04 - 2005/03

Committee Memberships 2

  • 金属材料研究所　計算材料学センター共同利用委員会

    2022/04 - Present

  • 金属材料研究所　広報班

    2022/04 - Present

Professional Memberships 2

  • 公益社団法人 日本セラミックス協会

    2015/01 - Present

  • 公益社団法人 金属学会

    2005/09 - Present

Research Interests 1

  • 第一原理計算、マテリアルズインフォマティクス、セラミック材料

Research Areas 2

  • Nanotechnology/Materials / Metallic materials /

  • Nanotechnology/Materials / Inorganic materials /

Awards 9

  1. 功績賞

    2024/03　公益社団法人 日本金属学会

  2. 2022 年度東北大学材料科学世界トップレベル研究拠点賞

    2022/10　「次世代材料探索に向けた計算材料データベース創製」

  3. 東工大の星「STAR」

    2021/03　「酸化物材料の計算データベース構築とその応用」

  4. 東京工業大学 挑戦的研究賞 末松特別賞

    2020/07　「物質中の点欠陥に関する統合的理解とその予測」

  5. 第15回村上奨励賞

    2018/09　公益社団法人日本金属学会　「半導体物性に関する理論研究」

  6. 第39回本多記念研究奨励賞

    2018/05　「第一原理計算に基づいた半導体物性理論の構築」

  7. The 25th Annual Meeting of MRS-J Award for Encouragement of Research

    2016/01　「Accurate Predictions of Point Defect Energetics in Semiconductors from First Principles」

  8. 第25回日本金属学会奨励賞 [物性部門]

    2015/09　公益社団法人日本金属学会

  9. 第53回セラミックス基礎科学討論会 国際セッション優秀賞

    2015/01

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Papers 94

  1. Bayesian Optimization with Gaussian Processes Assisted by Deep Learning for Material Designs

    Shin Kiyohara, Yu Kumagai

    The Journal of Physical Chemistry Letters　16　(21)　5244-5251　2025/05/19

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.jpclett.5c00592 　

    ISSN： 1948-7185

    eISSN： 1948-7185

  2. Oxygen Defect Engineering of Hexagonal Perovskite Oxides to Boost Catalytic Performance for Aerobic Oxidation of Sulfides to Sulfones

    Keiju Wachi, Masashi Makizawa, Takeshi Aihara, Shin Kiyohara, Yu Kumagai, Keigo Kamata

    ADVANCED FUNCTIONAL MATERIALS　2025/04/03

    DOI： 10.1002/adfm.202425452 　

    ISSN： 1616-301X

    eISSN： 1616-3028

  3. Role of hydrogen in the n-type oxide semiconductor MgIn2O4: Experimental observation of electrical conductivity and first-principles insight

    Saki Kudo, Tomoyuki Yamasaki, Issei Suzuki, Arunkumar Dorai, Rafael Costa-Amaral, Soungmin Bae, Yu Kumagai, Hiroshi Tanimura, Tetsu Ichitsubo, Takahisa Omata

    APL Materials　13　(4)　2025/04/01

    Publisher: AIP Publishing

    DOI： 10.1063/5.0253161 　

    eISSN： 2166-532X

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    Hydrogen impurities significantly influence the electrical conductivity of oxide semiconductors such as MgIn2O4, widely used in devices such as thin-film transistors. However, their role and chemical environment have not been fully clarified. This study investigated the conductivity of MgIn2O4 at elevated temperatures under air and H2 atmospheres, revealing higher and reversible conductivity in H2 due to hydrogen dissolution. Hall measurements, thermal desorption spectrometry, and nuclear magnetic resonance spectroscopy revealed that hydrogen dissolves in MgIn2O4, ionizing to produce electrons and interstitial protons. Density functional theory calculations indicate that hydrogen stabilizes near vacant octahedral cation sites, forming O–H bonds and shallow donor levels. Indium atoms at magnesium sites lead to shallow donor levels, whereas oxygen vacancies form deep levels. The results identify interstitial hydrogen and indium atoms at magnesium sites, rather than oxygen vacancies, as key donors under H2-rich or low oxygen conditions, providing insights for controlling the conductivity of MgIn2O4 in devices.

  4. Exploring Intrinsic and Extrinsic p-Type Dopability of Atomically Thin β-TeO2 from First Principles

    Rafael Costa-Amaral, Soungmin Bae, Thi Ngoc Huyen Vu, Yu Kumagai

    ACS Applied Materials & Interfaces　2024/12/26

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acsami.4c17868 　

    ISSN： 1944-8244

    eISSN： 1944-8252

  5. Universal Polaronic Behavior in Elemental Doping of MoS2 from First-Principles

    Soungmin Bae, Ibuki Miyamoto, Shin Kiyohara, Yu Kumagai

    ACS Nano　2024/12/02

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acsnano.4c08366 　

    ISSN： 1936-0851

    eISSN： 1936-086X

  6. Native defects and 𝑝-type dopability in transparent 𝛽-Te⁢O2: A first-principles study

    Vu Thi Ngoc Huyen, Soungmin Bae, Rafael Costa-Amaral, Yu Kumagai

    Physical Review Applied　22　(4)　2024/10/25

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevapplied.22.044065 　

    eISSN： 2331-7019

  7. First-principles calculations on dislocations in MgO

    Shin Kiyohara, Tomohito Tsuru, Yu Kumagai

    Science and Technology of Advanced Materials　25　(1)　2024/09/02

    Publisher: Informa UK Limited

    DOI： 10.1080/14686996.2024.2393567 　

    ISSN： 1468-6996

    eISSN： 1878-5514

  8. Size-Dependent Isovalent Impurity Doping for Ambipolar Control in Cu3N

    Kosuke Matsuzaki, Chen-Wei Chang, Teruya Nagafuji, Naoki Tsunoda, Yu Kumagai, Kenji Nomura, Fumiyasu Oba, Hideo Hosono

    Journal of the American Chemical Society　146　(35)　24630-24637　2024/08/24

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/jacs.4c08579 　

    ISSN： 0002-7863

    eISSN： 1520-5126

  9. Copper Phosphate Nanostructures as Catalysts for the Direct Methane Oxidation

    Aoi Matsuda, Takeshi Aihara, Shin Kiyohara, Yu Kumagai, Michikazu Hara, Keigo Kamata

    ACS Applied Nano Materials　7　(9)　10155-10167　2024/05/10

    DOI： 10.1021/acsanm.4c00549 　

    eISSN： 2574-0970

  10. Corrections on formation energies and eigenvalues of point defect calculations in two-dimensional materials

    Yu Kumagai

    Physical Review B　109　(5)　2024/02/14

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.109.054106 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  11. Structural Properties of Two-Dimensional Strontium Titanate: A First-Principles Investigation

    Shota Ono, Yu Kumagai

    Journal of the Physical Society of Japan　92　(11)　2023/11/15

    Publisher: Physical Society of Japan

    DOI： 10.7566/jpsj.92.114601 　

    ISSN： 0031-9015

    eISSN： 1347-4073

  12. Fully autonomous materials screening methodology combining first-principles calculations, machine learning and high-performance computing system

    Akira Takahashi, Kei Terayama, Yu Kumagai, Ryo Tamura, Fumiyasu Oba

    Science and Technology of Advanced Materials: Methods　3　(1)　2023/10/04

    Publisher: Informa UK Limited

    DOI： 10.1080/27660400.2023.2261834 　

    eISSN： 2766-0400

  13. Alkali Mono-Pnictides: A New Class of Photovoltaic Materials by Element Mutation

    Yu Kumagai, Seán R. Kavanagh, Issei Suzuki, Takahisa Omata, Aron Walsh, David O. Scanlon, Haruhiko Morito

    PRX Energy　2　(4)　2023/10/03

    Publisher: American Physical Society (APS)

    DOI： 10.1103/prxenergy.2.043002 　

    eISSN： 2768-5608

  14. Finite-size corrections to defect energetics along one-dimensional configuration coordinate

    Yu Kumagai

    Physical Review B　107　(22)　2023/06/08

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.107.l220101 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  15. Emergence of Dynamically‐Disordered Phases During Fast Oxygen Deintercalation Reaction of Layered Perovskite International-journal Peer-reviewed

    Takafumi Yamamoto, Shogo Kawaguchi, Taiki Kosuge, Akira Sugai, Naoki Tsunoda, Yu Kumagai, Kosuke Beppu, Takuya Ohmi, Teppei Nagase, Kotaro Higashi, Kazuo Kato, Kiyofumi Nitta, Tomoya Uruga, Seiji Yamazoe, Fumiyasu Oba, Tsunehiro Tanaka, Masaki Azuma, Saburo Hosokawa

    Advanced Science　2023/04/25

    DOI： 10.1002/advs.202301876 　

    ISSN： 2198-3844

    eISSN： 2198-3844

  16. Nanosized Ti-Based Perovskite Oxides as Acid–Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds International-journal Peer-reviewed

    Takeshi Aihara, Wataru Aoki, Shin Kiyohara, Yu Kumagai, Keigo Kamata, Michikazu Hara

    ACS Applied Materials & Interfaces　15　(14)　17957-17968　2023/04/03

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acsami.3c01629 　

    ISSN： 1944-8244

    eISSN： 1944-8252

  17. Computational Screening of p -Type Transparent Conducting Oxides Using the Optical Absorption Spectra and Oxygen-Vacancy Formation Energies International-journal Peer-reviewed

    Yu Kumagai

    Physical Review Applied　19　(3)　2023/03/20

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevapplied.19.034063 　

    eISSN： 2331-7019

  18. Adaptive sampling methods via machine learning for materials screening International-journal Peer-reviewed

    Akira Takahashi, Yu Kumagai, Hirotaka Aoki, Ryo Tamura, Fumiyasu Oba

    Science and Technology of Advanced Materials: Methods　2022/12/31

    Publisher: Informa {UK} Limited

    DOI： 10.1080/27660400.2022.2039573 　

  19. Unique Atomic and Electronic Structures of Oxygen Vacancies in Amorphous SnO2 from First Principles and Informatics International-journal International-coauthorship Peer-reviewed

    Shin Kiyohara, David Mora-Fonz, Alexander Shluger, Yu Kumagai, Fumiyasu Oba

    The Journal of Physical Chemistry C　2022/11/10

    DOI： 10.1021/acs.jpcc.2c04764 　

    ISSN： 1932-7447

    eISSN： 1932-7455

  20. Hole-Doping to a Cu(I)-Based Semiconductor with an Isovalent Cation: Utilizing a Complex Defect as a Shallow Acceptor International-journal Peer-reviewed

    Kosuke Matsuzaki, Naoki Tsunoda, Yu Kumagai, Yalun Tang, Kenji Nomura, Fumiyasu Oba, Hideo Hosono

    Journal of the American Chemical Society　2022/09/14

    DOI： 10.1021/jacs.2c06283 　

  21. Switchable Electric Dipole from Polaron Localization in Dielectric Crystals Invited Peer-reviewed

    Kazuki Morita, Yu Kumagai, Fumiyasu Oba, Aron Walsh

    Physical Review Letters　129　(1)　2022/06/28

    Publisher: American Physical Society ({APS})

    DOI： 10.1103/PhysRevLett.129.017601 　

  22. Recommendation of interstitial hydrogen positions in metal oxides International-journal Peer-reviewed

    Naoki Tsunoda, Yu Kumagai, Fumiyasu Oba

    Computational Materials Science　203　111068-111068　2022/02

    Publisher: Elsevier {BV}

    DOI： 10.1016/j.commatsci.2021.111068 　

  23. Tuning the optical band gap and electrical properties of NiO thin films by nitrogen doping: a joint experimental and theoretical study International-journal International-coauthorship Peer-reviewed

    Yong Wang, Stéphanie Bruyère, Yu Kumagai, Naoki Tsunoda, Fumiyasu Oba, Jaafar Ghanbaja, Hui Sun, Bo Dai, Jean-François Pierson

    RSC Advances　12　(34)　21940-21945　2022

    Publisher: Royal Society of Chemistry (RSC)

    DOI： 10.1039/d2ra01887j 　

    eISSN： 2046-2069

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    A joint experimental and theoretical study is presented to reveal the influence of nitrogen doping on the optical and electrical properties of NiO thin films.

  24. Defect formation and carrier compensation in layered oxychalcogenide La2CdO2Se2: an insight from first principles International-journal Peer-reviewed

    Tomoya Gake, Yu Kumagai, Akira Takahashi, Hidenori Hiramatsu, Fumiyasu Oba

    Journal of Materials Chemistry C　10　(44)　16828-16837　2022

    Publisher: Royal Society of Chemistry (RSC)

    DOI： 10.1039/D2TC03836F 　

    ISSN： 2050-7526

    eISSN： 2050-7534

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    Theoretical calculations explain that the experimentally reported nearly stoichiometric and electrical insulating behavior of undoped La2CdO2Se2 is due to the formation of Cd vacancies and interstitials.

  25. Insights into oxygen vacancies from high-throughput first-principles calculations International-journal Peer-reviewed

    Yu Kumagai, Naoki Tsunoda, Akira Takahashi, Fumiyasu Oba

    Physical Review Materials　2021/12/27

    DOI： 10.1103/PhysRevMaterials.5.123803 　

  26. Theoretical Prediction and Thin-Film Growth of the Defect-Tolerant Nitride Semiconductor YZn3N3 International-journal Peer-reviewed

    Ryosuke Kikuchi, Toru Nakamura, Takahiro Kurabuchi, Yasushi Kaneko, Yu Kumagai, Fumiyasu Oba

    Chemistry of Materials　2021/10/19

    DOI： 10.1021/acs.chemmater.1c02149 　

  27. Point defects in p -type transparent conductive CuMO2 ( M=Al , Ga, In) from first principles International-journal Peer-reviewed

    Tomoya Gake, Yu Kumagai, Akira Takahashi, Fumiyasu Oba

    Physical Review Materials　2021/10/08

    DOI： 10.1103/PhysRevMaterials.5.104602 　

  28. SrZn2N2 as a Solar Absorber: Theoretical Defect Chemistry and Synthesis by Metal Alloy Nitridation International-journal Peer-reviewed

    Ryosuke Kikuchi, Koki Ueno, Toru Nakamura, Takahiro Kurabuchi, Yasushi Kaneko, Yu Kumagai, Fumiyasu Oba

    Chemistry of Materials　33　(8)　2864-2870　2021/04/27

    Publisher: American Chemical Society ({ACS})

    DOI： 10.1021/acs.chemmater.1c00075 　

  29. Machine learning models for predicting the dielectric constants of oxides based on high-throughput first-principles calculations International-journal Peer-reviewed

    Akira Takahashi, Yu Kumagai, Jun Miyamoto, Yasuhide Mochizuki, Fumiyasu Oba

    Physical Review Materials　2020/10/09

    DOI： 10.1103/PhysRevMaterials.4.103801 　

  30. Data-Mining Element Charges in Inorganic Materials International-journal International-coauthorship Peer-reviewed

    Yu Ding, Yu Kumagai, Fumiyasu Oba, Lee A. Burton

    The Journal of Physical Chemistry Letters　8264-8267　2020/10/01

    Publisher: American Chemical Society ({ACS})

    DOI： 10.1021/acs.jpclett.0c02072 　

  31. Optical enhancement of dielectric permittivity in reduced lanthanum aluminate International-journal Peer-reviewed

    Takayuki Nagai, Akihide Kuwabara, Yu Kumagai, Ichiro Terasaki, Hiroki Taniguchi

    Physical Review B　101　(18)　2020/05/19

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.101.184114 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  32. Theoretical exploration of mixed-anion antiperovskite semiconductors M3XN(M=Mg,Ca,Sr,Ba;X=P,As,Sb,Bi) International-journal International-coauthorship Peer-reviewed

    Yasuhide Mochizuki, Ha-Jun Sung, Akira Takahashi, Yu Kumagai, Fumiyasu Oba

    Physical Review Materials　2020/04/13

    DOI： 10.1103/PhysRevMaterials.4.044601 　

  33. Phonon scattering limited mobility in the representative cubic perovskite semiconductors SrGeO3 , BaSnO3 , and SrTiO3 International-journal International-coauthorship Peer-reviewed

    Christian A. Niedermeier, Yu Kumagai, Keisuke Ide, Takayoshi Katase, Fumiyasu Oba, Hideo Hosono, Toshio Kamiya

    Physical Review B　101　(12)　2020/03/24

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.101.125206 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  34. Finite-size corrections for defect-involving vertical transitions in supercell calculations International-journal International-coauthorship Peer-reviewed

    Tomoya Gake, Yu Kumagai, Christoph Freysoldt, Fumiyasu Oba

    Physical Review B　2020/01/22

    DOI： 10.1103/PhysRevB.101.020102 　

  35. Stabilization of small polarons in BaTiO3 by local distortions International-journal Peer-reviewed

    Naoki Tsunoda, Yu Kumagai, Fumiyasu Oba

    Physical Review Materials　3　(11)　2019/11/27

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevmaterials.3.114602 　

    ISSN： 2475-9953

    eISSN： 2475-9953

  36. Correction: Effect of MnO<inf>2</inf> Crystal Structure on Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid (Journal of the American Chemical Society (2019) 141 (890-900) DOI: 10.1021/jacs.8b09917) International-journal Peer-reviewed

    Eri Hayashi, Yui Yamaguchi, Keigo Kamata, Naoki Tsunoda, Yu Kumagai, Fumiyasu Oba, Michikazu Hara

    Journal of the American Chemical Society　141　(46)　18642-18642　2019/11/20

    Publisher: American Chemical Society ({ACS})

    DOI： 10.1021/jacs.9b11588 　

    ISSN： 0002-7863

    eISSN： 1520-5126

  37. Spin-Glass Magnetic Properties of A-Site Columnar-Ordered Quadruple Perovskites Y2MnGa(Mn4–xGax)O12 with 0 ≤ x ≤ 3 International-journal International-coauthorship Peer-reviewed

    Ran Liu, Dmitry D. Khalyavin, Naoki Tsunoda, Yu Kumagai, Fumiyasu Oba, Yoshio Katsuya, Masahiko Tanaka, Kazunari Yamaura, Alexei A. Belik

    Inorganic Chemistry　2019/11/04

    Publisher: American Chemical Society ({ACS})

    DOI： 10.1021/acs.inorgchem.9b02542 　

  38. Achieving non-degenerate Zn3N2 thin films by near room temperature sputtering deposition International-journal International-coauthorship Peer-reviewed

    Wang Yong, Ohsawa Takeo, Kumagai Yu, Harada Kou, Oba Fumiyasu, Ohashi Naoki

    Applied Physics Letters　115　(9)　2019/08

    DOI： 10.1063/1.5101037 　

    ISSN： 0003-6951

  39. Energetics and electronic structure of native point defects in alpha-Ga2O3 International-journal Peer-reviewed

    Kobayashi Takuma, Gake Tomoya, Kumagai Yu, Oba Fumiyasu, Matsushita Yu-ichiro

    Applied Physics Express　12　(9)　2019/08

    DOI： 10.7567/1882-0786/ab3763 　

    ISSN： 1882-0778

    eISSN： 1882-0786

  40. Zinc-based spinel cathode materials for magnesium rechargeable batteries: toward the reversible spinel-rocksalt transition International-journal International-coauthorship Peer-reviewed

    Kohei Shimokawa, Taruto Atsumi, Maho Harada, Robyn E. Ward, Masanobu Nakayama, Yu Kumagai, Fumiyasu Oba, Norihiko L. Okamoto, Kiyoshi Kanamura, Tetsu Ichitsubo

    JOURNAL OF MATERIALS CHEMISTRY A　7　(19)　12225-12235　2019/05

    DOI： 10.1039/c9ta02281c 　

    ISSN： 2050-7488

    eISSN： 2050-7496

  41. First-principles study of self-trapped holes and acceptor impurities in Ga2O3 polymorphs International-journal Peer-reviewed

    Gake Tomoya, Kumagai Yu, Oba Fumiyasu

    Physical Review Materials　3　(4)　2019/04

    DOI： 10.1103/PhysRevMaterials.3.044603 　

    ISSN： 2475-9953

  42. Native point defects and carbon clusters in 4H-SiC: A hybrid functional study International-journal Peer-reviewed

    Kobayashi Takuma, Harada Kou, Kumagai Yu, Oba Fumiyasu, Matsushita Yu-ichiro

    Journal of Applied Physics　125　(12)　2019/03

    DOI： 10.1063/1.5089174 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  43. Direct Observation of Magnetization Reversal by Electric Field at Room Temperature in Co-Substituted Bismuth Ferrite Thin Film International-journal Peer-reviewed

    Shimizu Keisuke, Kawabe Ryo, Hojo Hajime, Shimizu Haruki, Yamamoto Hajime, Katsumata Marin, Shigematsu Kei, Mibu Ko, Kumagai Yu, Oba Fumiyasu, Azuma Masaki

    Nano Letters　19　(3)　1767-1773　2019/03

    DOI： 10.1021/acs.nanolett.8b04765 　

    ISSN： 1530-6984

  44. One-dimensionally extended oxygen vacancy states in perovskite oxides International-journal Peer-reviewed

    Tsunoda Naoki, Kumagai Yu, Araki Masahiko, Oba Fumiyasu

    Physical Review B　99　(6)　2019/02

    DOI： 10.1103/PhysRevB.99.060103 　

    ISSN： 2469-9950

  45. Effect of MnO2 Crystal Structure on Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid International-journal Peer-reviewed

    Hayashi Eri, Yamaguchi Yui, Kamata Keigo, Tsunoda Naoki, Kumagai Yu, Oba Fumiyasu, Hara Michikazu

    Journal of the American Chemical Society　141　(2)　890-900　2019/01

    DOI： 10.1021/jacs.8b09917 　

    ISSN： 0002-7863

    eISSN： 1520-5126

  46. Heterogeneously Catalyzed Aerobic Oxidation of Sulfides with a BaRuO<inf>3</inf> Nanoperovskite International-journal Peer-reviewed

    Keigo Kamata, Kosei Sugahara, Yuuki Kato, Satoshi Muratsugu, Yu Kumagai, Fumiyasu Oba, Michikazu Hara

    ACS Applied Materials and Interfaces　10　(28)　23792-23801　2018/07/18

    DOI： 10.1021/acsami.8b05343 　

    ISSN： 1944-8244

    eISSN： 1944-8252

  47. Design and exploration of semiconductors from first principles: A review of recent advances International-journal Peer-reviewed

    Fumiyasu Oba, Yu Kumagai

    Applied Physics Express　11　(6)　060101　2018/06/01

    DOI： 10.7567/APEX.11.060101 　

    ISSN： 1882-0786 1882-0778

  48. Point Defects and p-Type Doping in ScN from First Principles International-journal Peer-reviewed

    Yu Kumagai, Naoki Tsunoda, Fumiyasu Oba

    Physical Review Applied　9　(3)　034019　2018/03/22

    DOI： 10.1103/PhysRevApplied.9.034019 　

    ISSN： 2331-7019

  49. High-Mobility p-Type and n-Type Copper Nitride Semiconductors by Direct Nitriding Synthesis and In Silico Doping Design. International-journal Peer-reviewed

    Matsuzaki Kosuke, Harada Kou, Kumagai Yu, Koshiya Shogo, Kimoto Koji, Ueda Shigenori, Sasase Masato, Maeda Akihiro, Susaki Tomofumi, Kitano Masaaki, Oba Fumiyasu, Hosono Hideo

    Advanced Materials　30　(31)　e1801968　2018

    DOI： 10.1002/adma.201801968 　

    ISSN： 0935-9648

    eISSN： 1521-4095

  50. Polar metallic behavior of strained antiperovskites ACNi(3) (A = Mg, Zn, and Cd) from first principles International-journal Peer-reviewed

    Mochizuki Yasuhide, Kumagai Yu, Akamatsu Hirofumi, Oba Fumiyasu

    Physical Review Materials　2　(12)　2018

    DOI： 10.1103/PhysRevMaterials.2.125004 　

    ISSN： 2475-9953

  51. Strain-engineered Peierls instability in layered perovskite La3Ni2O7 from first principles International-journal Peer-reviewed

    Mochizuki Yasuhide, Akamatsu Hirofumi, Kumagai Yu, Oba Fumiyasu

    Physical Review Materials　2　(12)　2018

    DOI： 10.1103/PhysRevMaterials.2.125001 　

    ISSN： 2475-9953

  52. Effects of composition, crystal structure, and surface orientation on band alignment of divalent metal oxides: A first-principles study International-journal Peer-reviewed

    Hinuma Yoyo, Kumagai Yu, Tanaka Isao, Oba Fumiyasu

    Physical Review Materials　2　(12)　2018

    DOI： 10.1103/PhysRevMaterials.2.124603 　

  53. Electrically Benign Defect Behavior in Zinc Tin Nitride Revealed from First Principles International-journal Peer-reviewed

    Tsunoda Naoki, Kumagai Yu, Takahashi Akira, Oba Fumiyasu

    Physical Review Applied　10　(1)　014015　2018

    DOI： 10.1103/PhysRevApplied.10.011001 　

  54. Fast Diffusion of Multivalent Ions Facilitated by Concerted Interactions in Dual-Ion Battery Systems International-journal International-coauthorship Peer-reviewed

    Li Hongyi, Okamoto Norihiko L, Hatakeyama Takuya, Kumagai Yu, Oba Fumiyasu, Ichitsubo Tetsu

    Advanced Energy Materials　8　(27)　2018

    DOI： 10.1002/aenm.201801475 　

  55. Comparison of approximations in density functional theory calculations: Energetics and structure of binary oxides International-journal Peer-reviewed

    Yoyo Hinuma, Hiroyuki Hayashi, Yu Kumagai, Isao Tanaka, Fumiyasu Oba

    PHYSICAL REVIEW B　96　(9)　094102　2017/09

    DOI： 10.1103/PhysRevB.96.094102 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  56. Perovskite-Type InCoO3 with Low-Spin Co3+: Effect of In-O Covalency on Structural Stabilization in Comparison with Rare-Earth Series International-journal International-coauthorship Peer-reviewed

    Koji Fujita, Takahiro Kawamoto, Ikuya Yamada, Olivier Hernandez, Hirofumi Akamatsu, Yu Kumagai, Fumiyasu Oba, Pascal Manuel, Ryo Fujikawa, Suguru Yoshida, Masayuki Fukuda, Katsuhisa Tanaka

    INORGANIC CHEMISTRY　56　(18)　11113-11122　2017/09

    DOI： 10.1021/acs.inorgchem.7b01426 　

    ISSN： 0020-1669

    eISSN： 1520-510X

  57. Carrier-Induced Band-Gap Variation and Point Defects in Zn3N2 from First Principles International-journal Peer-reviewed

    Yu Kumagai, Kou Harada, Hirofumi Akamatsu, Kosuke Matsuzaki, Fumiyasu Oba

    PHYSICAL REVIEW APPLIED　8　(1)　014015　2017/07

    DOI： 10.1103/PhysRevApplied.8.014015 　

    ISSN： 2331-7019

  58. DFT investigation into the underperformance of sulfide materials in photovoltaic applications International-journal International-coauthorship Peer-reviewed

    Lee A. Burton, Yu Kumagai, Aron Walsh, Fumiyasu Oba

    JOURNAL OF MATERIALS CHEMISTRY A　5　(19)　9132-9140　2017/05

    DOI： 10.1039/c7ta00673j 　

    ISSN： 2050-7488

    eISSN： 2050-7496

  59. Functional electronic inversion layers at ferroelectric domain walls International-journal International-coauthorship Peer-reviewed

    J. A. Mundy, J. Schaab, Y. Kumagai, A. Cano, M. Stengel, I. P. Krug, D. M. Gottlob, H. Doğanay, M. E. Holtz, R. Held, Z. Yan, E. Bourret, C. M. Schneider, D. G. Schlom, D. A. Muller, R. Ramesh, N. A. Spaldin, D. Meier

    Nature Materials　16　(6)　622-627　2017/03/20

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/nmat4878 　

    ISSN： 1476-1122

    eISSN： 1476-4660

  60. Theory of ionization potentials of nonmetallic solids International-journal International-coauthorship Peer-reviewed

    Yu Kumagai, Keith T. Butler, Aron Walsh, Fumiyasu Oba

    PHYSICAL REVIEW B　95　(12)　125309　2017/03

    DOI： 10.1103/PhysRevB.95.125309 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  61. Unusual magnetic structure of the high-pressure synthesized perovskites ACrO(3) (A = Sc, In, Tl) International-journal International-coauthorship Peer-reviewed

    Lei Ding, Pascal Manuel, Dmitry D. Khalyavin, Fabio Orlandi, Yu Kumagai, Fumiyasu Oba, Wei Yi, Alexei A. Belik

    PHYSICAL REVIEW B　95　(5)　054432　2017/02

    DOI： 10.1103/PhysRevB.95.054432 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  62. Band alignment of semiconductors and insulators using dielectric-dependent hybrid functionals: Toward high-throughput evaluation International-journal Peer-reviewed

    Yoyo Hinuma, Yu Kumagai, Isao Tanaka, Fumiyasu Oba

    PHYSICAL REVIEW B　95　(7)　075302　2017/02

    DOI： 10.1103/PhysRevB.95.075302 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  63. Band structure diagram paths based on crystallography International-journal International-coauthorship Peer-reviewed

    Yoyo Hinuma, Giovanni Pizzi, Yu Kumagai, Fumiyasu Oba, Isao Tanaka

    COMPUTATIONAL MATERIALS SCIENCE　128　140-184　2017/02

    DOI： 10.1016/j.commatsci.2016.10.015 　

    ISSN： 0927-0256

    eISSN： 1879-0801

  64. Complex Structural Behavior of BiMn7O12 Quadruple Perovskite International-journal International-coauthorship Peer-reviewed

    Belik Alexei A, Matsushita Yoshitaka, Kumagai Yu, Katsuya Yoshio, Tanaka Masahiko, Stefanovich Sergey Yu, Lazoryak Bogdan I, Oba Fumiyasu, Yamaura Kazunari

    Inorganic Chemistry　56　(20)　12272-12281　2017

    DOI： 10.1021/acs.inorgchem.7b01723 　

  65. Ligancy-Driven Controlling of Covalency and Metallicity in a Ruthenium Two-Dimensional System International-journal Peer-reviewed

    Satoshi Toyoda, Katsutoshi Fukuda, Koji Horiba, Masaharu Oshima, Kazuhiro Kumagai, Yu Kumagai, Fumiyasu Oba, Yoshiharu Uchimoto, Eiichiro Matsubara

    CHEMISTRY OF MATERIALS　28　(16)　5784-5790　2016/08

    DOI： 10.1021/acs.chemmater.6b02019 　

    ISSN： 0897-4756

    eISSN： 1520-5002

  66. Electronic Structure and Defect Physics of Tin Sulfides: SnS, Sn2S3, and SnS2 International-journal International-coauthorship Peer-reviewed

    Yu Kumagai, Lee A. Burton, Aron Walsh, Fumiyasu Oba

    PHYSICAL REVIEW APPLIED　6　(1)　014009　2016/07

    DOI： 10.1103/PhysRevApplied.6.014009 　

    ISSN： 2331-7019

  67. Discovery of earth-abundant nitride semiconductors by computational screening and high-pressure synthesis International-journal International-coauthorship Peer-reviewed

    Yoyo Hinuma, Taisuke Hatakeyama, Yu Kumagai, Lee A. Burton, Hikaru Sato, Yoshinori Muraba, Soshi Iimura, Hidenori Hiramatsu, Isao Tanaka, Hideo Hosono, Fumiyasu Oba

    NATURE COMMUNICATIONS　7　11962　2016/06

    DOI： 10.1038/ncomms11962 　

    ISSN： 2041-1723

  68. Electronic Structure and Defect Chemistry of Tin(II) Complex Oxide SnNb2O6 International-journal Peer-reviewed

    Shota Katayama, Hiroyuki Hayashi, Yu Kumagai, Fumiyasu Oba, Isao Tanaka

    JOURNAL OF PHYSICAL CHEMISTRY C　120　(18)　9604-9611　2016/05

    DOI： 10.1021/acs.jpcc.6b01696 　

    ISSN： 1932-7447

    eISSN： 1932-7455

  69. LiNbO3-Type Oxide (Tl1–xScx)ScO3: High-Pressure Synthesis, Crystal Structure, and Electronic Properties International-journal International-coauthorship Peer-reviewed

    Alexei A. Belik, Wei Yi, Yu Kumagai, Yoshio Katsuya, Masahiko Tanaka, Fumiyasu Oba

    Inorganic Chemistry　55　(4)　1940-1945　2016/02/03

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.inorgchem.5b02915 　

    ISSN： 0020-1669

    eISSN： 1520-510X

  70. Categorization of surface polarity from a crystallographic approach International-journal Peer-reviewed

    Yoyo Hinuma, Yu Kumagai, Fumiyasu Oba, Isao Tanaka

    COMPUTATIONAL MATERIALS SCIENCE　113　221-230　2016/02

    DOI： 10.1016/j.commatsci.2015.11.042 　

    ISSN： 0927-0256

    eISSN： 1879-0801

  71. Screening procedure for structurally and electronically matched contact layers for high-performance solar cells: hybrid perovskites International-journal International-coauthorship Peer-reviewed

    Keith T. Butler, Yu Kumagai, Fumiyasu Oba, Aron Walsh

    JOURNAL OF MATERIALS CHEMISTRY C　4　(6)　1149-1158　2016

    DOI： 10.1039/c5tc04091d 　

    ISSN： 2050-7526

    eISSN： 2050-7534

  72. Intercalation and Push-Out Process with Spinel-to-Rocksalt Transition on Mg Insertion into Spinel Oxides in Magnesium Batteries International-journal Peer-reviewed

    Shinya Okamoto, Tetsu Ichitsubo, Tomoya Kawaguchi, Yu Kumagai, Fumiyasu Oba, Shunsuke Yagi, Kohei Shimokawa, Natsumi Goto, Takayuki Doi, Eiichiro Matsubara

    ADVANCED SCIENCE　2　(8)　1500072　2015/08

    DOI： 10.1002/advs.201500072 　

    eISSN： 2198-3844

  73. Toward "rocking-chair type" Mg-Li dual-salt batteries International-journal Peer-reviewed

    Ichitsubo, Tetsu, Okamoto, Shinya, Kawaguchi, Tomoya, Kumagai, Yu, Oba, Fumiyasu, Yagi, Shunsuke, Goto, Natsumi, Doi, Takayuki, Matsubara, Eiichiro

    Journal of Materials Chemistry a　3　(19)　10188-10194　2015

    DOI： 10.1039/c5ta01365h 　

    ISSN： 2050-7488

  74. Duality of Topological Defects in Hexagonal Manganites International-journal International-coauthorship Peer-reviewed

    Fei-Ting Huang, Xueyun Wang, Sinead M. Griffin, Yu Kumagai, Oliver Gindele, Ming-Wen Chu, Yoichi Horibe, Nicola A. Spaldin, Sang-Wook Cheong

    Physical Review Letters　113　(26)　2014/12/30

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevlett.113.267602 　

    ISSN： 0031-9007

    eISSN： 1079-7114

  75. Perovskite-Structure TIMnO3: A New Manganite with New Properties International-journal International-coauthorship Peer-reviewed

    Wei Yi, Yu Kumagai, Nicola A. Spaldin, Yoshitaka Matsushita, Akira Sato, Igor A. Presniakov, Alexey V. Sobolev, Yana S. Glazkova, Alexei A. Belik

    INORGANIC CHEMISTRY　53　(18)　9800-9808　2014/09

    DOI： 10.1021/ic501380m 　

    ISSN： 0020-1669

    eISSN： 1520-510X

  76. First-principles study of point defects in chalcopyrite ZnSnP2 International-journal International-coauthorship Peer-reviewed

    Yu Kumagai, Minseok Choi, Yoshitaro Nose, Fumiyasu Oba

    PHYSICAL REVIEW B　90　(12)　125202　2014/09

    DOI： 10.1103/PhysRevB.90.125202 　

    ISSN： 1098-0121

    eISSN： 1550-235X

  77. Electrostatics-based finite-size corrections for first-principles point defect calculations International-journal Peer-reviewed

    Yu Kumagai, Fumiyasu Oba

    PHYSICAL REVIEW B　89　(19)　195205　2014/05

    DOI： 10.1103/PhysRevB.89.195205 　

    ISSN： 1098-0121

    eISSN： 1550-235X

  78. Band offsets of CuInSe2/CdS and CuInSe2/ZnS (110) interfaces: A hybrid density functional theory study International-journal Peer-reviewed

    Yoyo Hinuma, Fumiyasu Oba, Yu Kumagai, Isao Tanaka

    PHYSICAL REVIEW B　88　(3)　2013/07

    DOI： 10.1103/PhysRevB.88.035305 　

    ISSN： 1098-0121

  79. Strong Spin-Lattice Coupling Through Oxygen Octahedral Rotation in Divalent Europium Perovskites International-journal Peer-reviewed

    Hirofumi Akamatsu, Yu Kumagai, Fumiyasu Oba, Koji Fujita, Katsuhisa Tanaka, Isao Tanaka

    ADVANCED FUNCTIONAL MATERIALS　23　(15)　1864-1872　2013/04

    DOI： 10.1002/adfm.201202477 　

    ISSN： 1616-301X

    eISSN： 1616-3028

  80. Structural domain walls in polar hexagonal manganites International-journal International-coauthorship Peer-reviewed

    Yu Kumagai, Nicola A. Spaldin

    Nature Communications　4　(1)　2013/02/26

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/ncomms2545 　

    eISSN： 2041-1723

  81. Anti-ferrodistortive-Like Oxygen-Octahedron Rotation Induced by the Oxygen Vacancy in Cubic SrTiO3 International-journal International-coauthorship Peer-reviewed

    Minseok Choi, Fumiyasu Oba, Yu Kumagai, Isao Tanaka

    ADVANCED MATERIALS　25　(1)　86-90　2013/01

    DOI： 10.1002/adma.201203580 　

    ISSN： 0935-9648

  82. Scaling Behavior and Beyond Equilibrium in the Hexagonal Manganites International-journal International-coauthorship Peer-reviewed

    S. M. Griffin, M. Lilienblum, K. T. Delaney, Y. Kumagai, M. Fiebig, N. A. Spaldin

    Physical Review X　2　(4)　2012/12/27

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevx.2.041022 　

    eISSN： 2160-3308

  83. Ionization potentials of (112) and (112¯) facet surfaces of CuInSe2 and CuGaSe2 International-journal Peer-reviewed

    Hinuma Yoyo, Oba Fumiyasu, Kumagai Yu, Tanaka Isao

    Physical Review B　86　(24)　2012/12

    Publisher: American Physical Society

    DOI： 10.1103/PhysRevB.86.245433 　

    ISSN： 1098-0121

    More details Close

    The ionization potentials of the faceted and nonfaceted (110) surfaces of CuInSe2 (CIS) and CuGaSe2 (CGS), which are key components of CuIn1−xGaxSe2 (CIGS) thin-film solar cells, are investigated using first-principles calculations based on a hybrid Hartree-Fock density functional theory approach. Slab models of the chalcopyrite (110) surface with both (112) and (112̅ ) facets on each surface of the slab are employed. Surface energy evaluations point out that two types of faceted surfaces with point defects, namely a combination of CuIn (CuGa) and InCu (GaCu) antisites and a combination of Cu vacancies and InCu (GaCu) antisites, are the most stable depending on the chemical potentials. The ionization potentials are evaluated with two definitions: One highly sensitive to and the other less sensitive to localized surface states. The latter varies by 0.4 eV in CIS and 0.5 eV in CGS with the surface structure. The ionization potentials are reduced by 0.2 eV for faceted surfaces with CuIn (CuGa) and InCu (GaCu) antisites when the effects of the localized surface states are considered. The values of both ionization potentials are similar between CIS and CGS with a difference of about 0.1 eV for the most stable surface structures.

  84. Observation of persistent centrosymmetricity in the hexagonal manganite family International-journal International-coauthorship Peer-reviewed

    Yu Kumagai, Alexei A. Belik, Martin Lilienblum, Naëmi Leo, Manfred Fiebig, Nicola A. Spaldin

    Physical Review B　85　(17)　2012/05/15

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.85.174422 　

    ISSN： 1098-0121

    eISSN： 1550-235X

  85. Crystal and Electronic Structure and Magnetic Properties of Divalent Europium Perovskite Oxides EuMO3 (M = Ti, Zr, and Hf): Experimental and First-Principles Approaches International-journal Peer-reviewed

    Hirofumi Akamatsu, Koji Fujita, Hiroyuki Hayashi, Takahiro Kawamoto, Yu Kumagai, Yanhua Zong, Koji Iwata, Fumiyasu Oba, Isao Tanaka, Katsuhisa Tanaka

    INORGANIC CHEMISTRY　51　(8)　4560-4567　2012/04

    DOI： 10.1021/ic2024567 　

    ISSN： 0020-1669

    eISSN： 1520-510X

  86. Anisotropic conductance at improper ferroelectric domain walls International-journal International-coauthorship Peer-reviewed

    D. Meier, J. Seidel, A. Cano, K. Delaney, Y. Kumagai, M. Mostovoy, N. A. Spaldin, R. Ramesh, M. Fiebig

    Nature Materials　11　(4)　284-288　2012/02/26

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/nmat3249 　

    ISSN： 1476-1122

    eISSN： 1476-4660

  87. First-principles calculations of the phase diagrams and band gaps in CuInSe2-CuGaSe2 and CuInSe2-CuAlSe2 pseudobinary systems International-journal Peer-reviewed

    Yu Kumagai, Yoshito Soda, Fumiyasu Oba, Atsuto Seko, Isao Tanaka

    PHYSICAL REVIEW B　85　(3)　2012/01

    DOI： 10.1103/PhysRevB.85.033203 　

    ISSN： 1098-0121

  88. Ground-state search in multicomponent magnetic systems International-journal Peer-reviewed

    Yu Kumagai, Atsuto Seko, Fumiyasu Oba, Isao Tanaka

    PHYSICAL REVIEW B　85　(1)　2012/01

    DOI： 10.1103/PhysRevB.85.012401 　

    ISSN： 1098-0121

  89. Antiferromagnetic superexchange via 3d states of titanium in EuTiO3 as seen from hybrid Hartree-Fock density functional calculations International-journal Peer-reviewed

    Hirofumi Akamatsu, Yu Kumagai, Fumiyasu Oba, Koji Fujita, Hideo Murakami, Katsuhisa Tanaka, Isao Tanaka

    PHYSICAL REVIEW B　83　(21)　2011/06

    DOI： 10.1103/PhysRevB.83.214421 　

    ISSN： 1098-0121

    eISSN： 2469-9969

  90. First-principles study of defect-induced potentials in Ca2CuO2Cl2 International-journal Peer-reviewed

    Yu Kumagai, Fumiyasu Oba, Ikuya Yamada, Masaki Azuma, Isao Tanaka

    PHYSICAL REVIEW B　80　(8)　2009/08

    DOI： 10.1103/PhysRevB.80.085120 　

    ISSN： 1098-0121

  91. First-principles investigation of atomic structures and stability of proton-exchanged layered sodium titanate International-journal Peer-reviewed

    Masahiro Mori, Yu Kumagai, Katsuyuki Matsunaga, Isao Tanaka

    Physical Review B　79　(14)　2009/04/24

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.79.144117 　

    ISSN： 1098-0121

    eISSN： 1550-235X

  92. All-electron CI calculations of 3d transition-metal L2,3XANES using zeroth-order regular approximation for relativistic effects International-journal Peer-reviewed

    Yu Kumagai, Hidekazu Ikeno, Isao Tanaka

    Journal of Physics: Condensed Matter　21　(10)　104209-104209　2009/02/10

    Publisher: IOP Publishing

    DOI： 10.1088/0953-8984/21/10/104209 　

    ISSN： 0953-8984

    eISSN： 1361-648X

  93. Effects of crystal structure on Co-L(2,3) x-ray absorption near-edge structure and electron-energy-loss near-edge structure of trivalent cobalt oxides International-journal Peer-reviewed

    Yu Kumagai, Hidekazu Ikeno, Fumiyasu Oba, Katsuyuki Matsunaga, Isao Tanaka

    PHYSICAL REVIEW B　77　(15)　2008/04

    DOI： 10.1103/PhysRevB.77.155124 　

    ISSN： 1098-0121

  94. First-principles multi-electron calculations for L-2,L-3 ELNES/XANES of 3d transition metal monoxides International-journal Peer-reviewed

    Hidekazu Ikeno, Teruyasu Mizoguchi, Yukinori Koyama, Yu Kumagai, Isao Tanaka

    ULTRAMICROSCOPY　106　(11-12)　970-975　2006/10

    DOI： 10.1016/j.ultramic.2006.05.005 　

    ISSN： 0304-3991

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Misc. 19

  1. 計算材料データベース開発ー酸化物を例としてー Invited Peer-reviewed

    熊谷 悠

    CERAMICS JAPAN　58　672-675　2023/10

  2. Computational materials database for oxides Invited Peer-reviewed

    Yu Kumagai

    92　(3)　172-176　2023/03

    DOI： 10.11470/oubutsu.92.3_172 　

  3. 第一原理計算に基づく非金属物質中の点欠陥挙動に関する理論的研究 Invited Peer-reviewed

    熊谷 悠

    まてりあ　58　(6)　320-327　2019/06

  4. 半導体材料探索に向けた計算材料データベースの開発 Invited Peer-reviewed

    熊谷 悠, 大場 史康

    化学工業　69　(1)　18-26　2018/01

  5. Prediction of Fundamental Properties of Semiconductors and Materials Exploration Using First-Principles Calculations Invited Peer-reviewed

    Fumiyasu Oba, Yoyo Hinuma, Yu Kumagai

    56　(9)　554-559　2017/09

    Publisher: Japan Institute of Metals

    DOI： 10.2320/materia.56.554 　

    ISSN： 1340-2625

    eISSN： 1884-5843

  6. 半導体材料探索に向けた計算データベースの開発 Invited Peer-reviewed

    熊谷 悠, 大場 史康

    固体物理　52　(11)　151-158　2017

  7. 先進計算科学による半導体物性の高精度予測と新物質探索 Invited Peer-reviewed

    大場 史康, 日沼 洋陽, 熊谷 悠

    工業材料　64　(7)　30-34　2016/06

  8. 半導体点欠陥の第一原理計算 Invited Peer-reviewed

    熊谷 悠

    まてりあ　55　(5)　221-224　2016/05

  9. First-principles Study of Point Defects in Cupper Nitride Peer-reviewed

    K. Harada, Y. Kumagai, K. Matsuzaki, T. Susaki, F. Oba

    AMTC Letters　5　138-13　2016

  10. Ab Initio Study of Point Defects in Tin Sulfides Peer-reviewed

    Y. Kumagai, L. A. Burton, A. Walsh, F. Oba

    AMTC Letters　5　140-141　2016

  11. 過去，現在，そして未来の研究 Invited Peer-reviewed

    熊谷 悠

    セラミックス誌　50　(10月)　2015/10

  12. 半導体の基礎物性・格子欠陥特性の高精度理論予測と物質・材料探索への展開 Invited Peer-reviewed

    大場 史康, 日沼 洋陽, 熊谷 悠

    セラミックス誌　50　(7月)　542-545　2015/07

  13. Finite-size correction for first-principles point defect calculations using a supercell approach Peer-reviewed

    Y. Kumagai, F. Oba

    AMTC Letters　4　88-89　2014

  14. 第一原理熱力学計算によるセラミックス材料の相平衡

    世古 敦人, 熊谷 悠, 大場 史康, 田中 功

    セラミックス誌　47　(7月)　2012/07

  15. Role of d states of B-site cations for spin-lattice coupling in Eu2+ perovskite oxides Peer-reviewed

    H. Akamatsu, F. Oba, Y. Kumagai, K. Fujita, K. Tanaka, I. Tanaka

    AMTC Letters　3　250-251　2012

  16. Theoretical calculation of structures and stability of layered titanates as precursor of nanotubes Peer-reviewed

    AMTC Letters　2　188-189　2010

  17. First-Principles Study of Magnetism and Electronic Structure in Eu2+ Perovskite Oxides Peer-reviewed

    H. Akamatsu, Y. Kumagai, F. Oba, K. Fujita, K. Tanaka, I. Tanaka

    AMTC Letters　2　162-163　2010

  18. Ground-State Structures in MgO-NiO Crystalline Solutions Peer-reviewed

    Y. Kumagai, A. Seko, F. Oba, I. Tanaka

    AMTC Letters　2　180-181　2010

  19. First-principles Study of Co L2,3 XANES and ELNES of Trivalent Cobalt Compounds Peer-reviewed

    AMTC Letters　1　138-139　2008

Show all ︎Show first 5

Presentations 43

  1. 第一原理計算とMIによる欠陥を考慮した新材料探索 Invited

    熊谷 悠

    スーパーコンピュータワークショップ2024　2025/01/16

  2. Defects in Semiconductors: A First-Principles Investigation

    Yu Kumagai

    SMS2024　2024/11/27

  3. Accurate Calculations for Point Defects in Non-Metallic Materials and Their Applications Invited

    Yu Kumagai

    ENGE2024　2024/11/26

  4. 点欠陥特性を考慮した半導体材料スクリーニング Invited

    熊谷 悠

    日本金属学会第2分野主催 「情報・デバイス」と「材料」研究会　2024/11/08

  5. 欠陥形成エネルギーの高精度計算 と機械学習による予測 Invited

    熊谷 悠

    日本セラミックス協会 第37回秋季シンポジウム　2024/09/10

  6. Insights on Point Defect Energetics in Non-Metallic Solids under Periodic Boundary Conditions Invited

    Yu Kumagai

    2024 Defects in Semiconductors Conference GRC　2024/08/07

  7. High-throughput calculations on oxygen vacancies and their applications Invited

    Yu Kumagai

    ICC'10　2024/07/15

  8. High-accuracy calculation of point defects inside non-metallic materials and its applications Invited

    Yu Kumagai

    ECAPD 2024　2024/06/18

  9. 非金属物質内部の点欠陥の高精度計算とその応用 Invited

    熊谷 悠

    日本金属学会 2024年春期大会　2024/03/15

  10. 非金属物質中の点欠陥に関する第一原理計算 Invited

    熊谷 悠

    物質科学シミュレーションと先端実験のデータ連携　2024/02/19

  11. 大学研究者によるMI研究事例の紹介 Invited

    熊谷 悠

    第3回新材料・新機能創生研究会　2024/01/19

  12. Alkali mono-pnictides: a new class of photovoltaic materials by element mutation

    Yu Kumagai

    Summit of Materials Science 2023　2023/11/21

  13. エレメントミューテーションによる新規太陽電池材料の提案

    熊谷 悠

    計算科学と情報学を用いた材料開発の新展開ー2023　2023/08/24

  14. Construction of a Computational Materials Database for Oxides Invited

    Yu Kumagai

    2023 Japan-America Frontiers of Engineering Symposium　2023/07/18

  15. エレメントミューテーションによる新規太陽電池材料の提案

    熊谷 悠

    E-IMR Summer Meeting2023　2023/06/19

  16. 非金属物質中の点欠陥を対象とした 理論計算の進展 Invited

    熊谷 悠

    PCoMSシンポジウム　2023/02/13

  17. 酸化物を対象とした計算材料データベースの構築 Invited

    熊谷 悠

    透明酸化物光・電子材料研究会　2022/10/14

  18. 第一原理計算の材料科学への応用 Invited

    熊谷 悠

    東京大学 マテリアルズ・インフォマティクスの基礎と応用　2022/09/22

  19. 酸化物に関する計算材料データベース構築 Invited

    熊谷 悠

    日本セラミックス協会第35回秋季シンポジウム

  20. 点欠陥特性に関する計算材料データベース構築 Invited

    熊谷 悠

    電気化学界面シミュレーション 第2回研究会　2022/08/30

  21. 計算科学を使った物性予測はどれほど進歩しているのか Invited

    熊谷 悠

    学振69委員会　2022/08/02

  22. 酸素空孔に関する系統的計算と機械学習 Invited

    熊谷 悠

    日本化学会第102春季年会

  23. 計算材料データベースの構築に関して Invited

    熊谷 悠

    第６回アドバンス・シミュレーション・セミナー2021　2021/10/29

  24. 理論計算・データ科学による機能性セラミックス材料開発の革新 Invited

    熊谷 悠

    金属材料研究所ワークショップ・セラミックス材料をめぐる最近の研究動向　2021/10/29

  25. 非金属物質中の点欠陥を対象とした系統的第一原理計算 Invited

    熊谷 悠

    第1回計算イオニクス研究会　2021/07/28

  26. 計算材料データベースの開発 Invited

    熊谷 悠

    第88回マテリアルズ・テーラリング研究会　2021/04/17

  27. 計算材料データベース構築とその応用 Invited

    熊谷 悠

    日本セラミックス協会2021年年会

  28. 酸化物に関する計算材料データベース構築 Invited

    熊谷 悠

    2020年度第5回物性アプリオープンフォーラム　2021/01/13

  29. 酸化物物性と酸素空孔に関する系統的計算 Invited

    熊谷 悠

    第30回日本MRS年次大会

  30. 酸化物物性の系統的計算 Invited

    熊谷 悠

    第66回応用物理学会春季学術講演会

  31. 機械学習を用いた酸化物物性予測 Invited

    熊谷 悠

    第 8 回・酸化物研究の新機軸に向けた学際討論会　2019/01/25

  32. 半導体中点欠陥の第一原理計算とその応用 Invited

    熊谷 悠

    日本金属学会第163回秋期講演大会2018

  33. 半導体材料開発のための計算材料データベース Invited

    熊谷 悠

    日本物理学会第73回年次大会　2018/03/25

  34. Computational materials database toward discovering novel semiconductors Invited

    熊谷 悠

    第32回コンピュテーショナル・マテリアルズ・デザインワークショップ　2018/03/02

  35. 半導体材料開発のための第一原理計算 Invited

    熊谷 悠

    ポスト新機能物質開発のための戦略会議

  36. First-principles calculations on point defects in semiconductors and insulators Invited

    熊谷 悠

    The 20th Asian Workshop on First-Principles Electronic Structure Calculations

  37. 半導体材料探索に向けた計算データベースの開発 Invited

    熊谷 悠

    新機能デバイス・高性能材料のための産官学連携フォーラム 第３回会合　2017/09/11

  38. First-principles calculations on point defects in semiconductors Invited

    熊谷 悠

    Frontiers in Materials Science 2017

  39. Computational materials database toward discovering novel semiconductors Invited

    熊谷 悠

    Interdisciplinary symposium on modern density functional theory – iDFT

  40. First-principles investigation of point defects in non-metallic materials Invited

    熊谷 悠

    第26回日本MRS年次大会

  41. 第一原理に基づく点欠陥計算の高精度化とその応用 Invited

    熊谷 悠

    日本金属学会秋期講演大会2015

  42. Predictions of point defect properties in semiconductors Invited

    熊谷 悠

    PACRIM11

  43. Structural domain walls in polar hexagonal manganites Invited

    熊谷 悠

    APS March meeting 2014

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Industrial Property Rights 7

  1. 無機化合物半導体、その製造方法、およびそれを用いた光エネルギー変換素子

    特許6715471

    Property Type: Patent

  2. 光エネルギー変換素子およびそれを具備するデバイス

    菊地 諒介, 中村 透, 藏渕 孝浩, 羽藤 一仁, 大場 史康, 熊谷 悠

    特許6562286

    Property Type: Patent

  3. 多接合型光エネルギー変換素子、およびそれを具備するデバイス

    菊地 諒介, 中村 透, 藏渕 孝浩, 羽藤 一仁, 大場 史康, 熊谷 悠, 赤松 寛文, バートンリーアラン

    Property Type: Patent

  4. 窒化銅半導体およびその製造方法

    松崎 功佑, 細野 秀雄, 大場 史康, 熊谷 悠, 原田 航, 雲見 日出也

    特許6951734

    Property Type: Patent

  5. 窒化亜鉛系化合物およびその製造方法

    大場 史康, 細野 秀雄, 平松 秀典, 雲見 日出也, 熊谷 悠, 飯村 壮史, 村場 善行, リー, アラン・バートン, 田中 功, 日沼 洋陽

    特許6773666

    Property Type: Patent

  6. 多接合型光エネルギー変換素子およびそれを具備するデバイス、並びにＳｒＺｎ２Ｎ２の製造方法

    上野 航輝, 菊地諒介, 中村透, 藏渕孝浩, 金子 泰, 羽藤 一仁, 大場 史康, 熊谷 悠

    Property Type: Patent

  7. 多接合型光エネルギー変換素子、およびそれを具備するデバイス

    中村 透, 藏渕 孝浩, 菊地諒介, 羽藤 一仁, 大場 史康, 熊谷 悠, 赤松 寛文, バートンリーアラン

    Property Type: Patent

Show all Show first 5

Research Projects 9

  1. Investigation of oxygen vacancies on oxide surfaces

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2022/04 - 2025/03

  2. 非晶質前駆体を用いた高機能性ペロブスカイト関連化合物の開発

    熊谷 悠

    Offer Organization: JST

    System: CREST

    Institution: 東北大学

    2022/10 -

  3. Understanding and prediction of band-edge energies via machine learning

    Kumagai Yu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)

    Category: Grant-in-Aid for Challenging Research (Exploratory)

    Institution: Tokyo Institute of Technology

    2020/07 - 2022/03

    More details Close

    In recent years, improvements in computer performance and advances in computational methods have made it possible to calculate band edge positions with high precision using first-principles calculations that solve the fundamental equations of quantum mechanics. In this study, we performed systematic first-principles calculations for about 100 oxide band-edge positions and aimed to systematically understand the characteristics of each band-edge material based on the obtained data. The results show that the upper valence band edge (VBM) positions of the same oxides are widely distributed ranging about 4 eV. While the VBM is lower in boron oxides, it is larger when the VBM is composed of Cu-3d orbitals and isolated electron pair orbitals of As and Sb.

  4. Systematic understanding of oxygen vacancies and prediction by machine learning

    Kumagai Yu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tokyo Institute of Technology

    2019/04 - 2022/03

    More details Close

    Conventional point defect calculations were limited to individual studies of specific materials due to the complexity of the process. However, computer performance has improved dramatically over the years, and in recent years, it has become sufficient to perform systematic point defect calculations. Therefore, we performed systematic point defect calculations for several thousand materials and constructed a database of calculated materials. Furthermore, based on this database, we predicted point defect formation energies by machine learning and discovered peculiar phenomena related to point defects.

  5. 日本板硝子材料工学助成会

    2019 - 2020

  6. 半導体材料開発のための計算データベース構築

    熊谷 悠

    Offer Organization: 科学技術振興機構

    System: 戦略的な研究開発の推進 戦略的創造研究推進事業 さきがけ

    Institution: 東京工業大学

    2016 - 2019

    More details Close

    計算材料データベースは,様々な材料設計に重要な指針を与える現代の材料研究では重要な位置付けにあります.しかしながら従来のデータベースでは,電子材料の研究に適した計算物性値が不足しています.そこで本研究では,バンドギャップを有する非金属材料を対象に,点欠陥やイオン化ポテンシャルなど多様な物性値を,第一原理計算と機械学習を組み合わせることで,高精度かつ高速に計算することを目的とします.

  7. Development of computational techniques for discovering novel semiconductors from first principles

    Kumagai Yu, OBA Fumiyasu, TSUNODA Naoki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (A)

    Category: Grant-in-Aid for Young Scientists (A)

    Institution: Tokyo Institute of Technology

    2015/04 - 2018/03

    More details Close

    Thanks to the progress on the computer power and first-principles calculation techniques, it becomes possible to seek for new materials from first-principles calculations nowadays. As a result, computational material databases have been continuously developed by some groups in the world in the past decade. Such databases are very useful for discovering novel materials. However, discovery of new semiconductors with such databases was difficult in general because physical properties related to semiconductor applications are widespread, and some of them are difficult or even impossible to calculate from first-principles. Therefore, in this study, we have developed theory, calculation techniques and programs that are indispensable for discovering semiconductor materials from first-principles calculations.

  8. 村田学術振興財団研究助成

    Offer Organization: 村田学術振興財団

    2018 -

  9. 研究の種発掘

    Offer Organization: 東京工業大学学内研究助成

    2017 -

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Teaching Experience 4

  1. 解析力学　東北大学

  2. Introduction to Solid State Science　Tokyo Institute of Technology

  3. 先進材料概論　東京工業大学

  4. 材料数理科学　東京工業大学

Works 2

  1. vise

    2021/04/01 - Present

    Type: Software

    More details Close

    VASP Integrated Supporting Environment (vise) is a collection of tools that supports VASP users to prepare input files for the VASP calculations, handle its calculation errors, and analyze its results.

  2. pydefect

    2021/04/01 -

    Type: Software