特異なバンド構造と電子相関の協力効果による新奇量子伝導現象に関する理論的研究

2008 Fiscal Year Annual Research Report

• Project/Area Number: 20540350
• Research Institution: The University of Electro-Communications
• Principal Investigator: 黒木 和彦 The University of Electro-Communications, 電気通信学部, 教授 (10242091)
• Keywords: バンド構造 / 電子相関 / 超伝導 / 熱電効果 / 層状窒化物 / 酸化物 / 鉄ニクタイド

Research Abstract

(1) 層状窒化物超伝導
層状窒化物MNC1 (M=Hf, Zr)に対して第一原理計算のバンド構造を再現する有効模型を構築し、スピン揺らぎ媒介によるd波超伝導の可能性を提唱した。ギャップのバンド・フィリング依存性を議論し、実験との対応を検証しつつある。
(2) 鉄ニクタイド超伝導
新しく発見された鉄ニクタイド超伝導体に対して、第一原理計算を元に5バンドの有効模型を構築し、非連結フェルミ面を有効に利用したスピン揺らぎ媒介メカニズムを提唱した。この有効模型はその後、国内外の多くの理論グループに用いられている。
(3) 新規超伝導探索
銅酸化物、鉄ニクタイド化合物以外のd電子系高温超伝導体を探索するため、既存物質以外の第一原理計算に基づく有効模型構築に着手した。
(4) 熱電効果
LiRh_2 O_4, CuRhO_2, LaRhO_3の大きな熱起電力の起源をバンド構造の観点から明らかにした。また、LaCoO_3, SrTiO_3の大きな熱起電力の起源についても、研究に着手した。

Research Products

• [Journal Article] Erratum : Unconventional Pairing Originating from the Disconnected Fermi Surfaces of Superconducting LaFeAsO_<1-x>F_x (2009)
  • Author(s): K. Kuroki, S. Onari, R. Arita, H. Usui, Y. Tanaka, H. Kontani, H. Aoki
  • Journal Title: Physical Review Letters 102 Pages: 109002(E)
  • Peer Reviewed
• [Journal Article] Unconventional pairing originating from disconnected Fermi surfaces in the iron-based superconductor (2009)
  • Author(s): K. Kuroki, S. Onari, R. Arita, H. Usui, Y. Tanaka, H. Kontani, H. Aoki
  • Journal Title: New Journal of Physics 11 Pages: 025017-1-8
  • Peer Reviewed
• [Journal Article] Strong Parity Mixing in the Fulde-Ferrell-Larkin-Ovchinnikov Superconductivity in Systems with Coexi sting Spin and Charge fluctuations (2009)
  • Author(s): H. Aizawa, K. Kuroki, T. Yokoyama, Y. Tanaka
  • Journal Title: Physical Review Letters 102 Pages: 016403-1-4
  • Peer Reviewed
• [Journal Article] Minimal model for study on superconductivity in LaFeAsO_<1-x>F_x based on ab-initio downfolding (2009)
  • Author(s): R. Arita, S. Onari, H. Usui, K. Kuroki, Y. Tanaka, H. Kontani, H. Aoki
  • Journal Title: Jounal of Physics : Conference Series (proc. LT 25) 150 Pages: 052010-1-4
  • Peer Reviewed
• [Journal Article] Competition between triplet, singlet and FFLO states in organic superconductors (TMTSF)_2X under magnetic field (2009)
  • Author(s): H. Aizawa, K. Kuroki, T. Yokoyama, Y. Tanaka
  • Journal Title: Jounal of Physics : Conference Series (proc. LT 25) 150 Pages: 052503-1-4
  • Peer Reviewed
• [Journal Article] Unconventional pairing in doped band insulators on a honeycomblattice : application to superconducting β-MNCl (M=Hf, Zr) (2009)
  • Author(s): K. Kuroki
  • Journal Title: Jounal of Physics : Conference Series (proc. LT 25) 150 Pages: 052136-1-4
  • Peer Reviewed
• [Journal Article] An improved alogorithm for the functional renormalization group and its application to the 2D Hubbard model (2009)
  • Author(s): H. Takashima, R. Arita, K. Kuroki, H. Aoki
  • Journal Title: Jounal of Physics : Conference Series(proc. LT 25) 150 Pages: 052261-1-4
  • Peer Reviewed
• [Journal Article] Study on the origin of large thermopower in hole doped LaRhO_3 based on ab-initio downfolding (2009)
  • Author(s): H. Usui, K. Kuroki, R. Arita
  • Journal Title: Jounal of Physics : Conference Series(proc. LT 25) 150 Pages: 022095-1-4
  • Peer Reviewed
• [Journal Article] Unconventional Pairing Originating from the Disconnected Fermi Surfaces of Superconducting LaFeAsO_<1-x>F_x (2008)
  • Author(s): K. Kuroki, S. Onari, R. Arita, H. Usui, Y. Tanaka, H. Kontani, H. Aoki
  • Journal Title: Physical Review Letters 101 Pages: 087004-1-4
  • Peer Reviewed
• [Journal Article] Strong magnetic field enhancement of spin triplet pairing arising from coexisting 2k_F spin and 2k_F charge fluctuations (2008)
  • Author(s): H. Aizawa, K. Kuroki, Y. Tanaka
  • Journal Title: Physical Review B 77 Pages: 144513-1-5
  • Peer Reviewed
• [Journal Article] Origin of large thermopower in LiRh_2O_4 : Calculation of the Seebeck coefficient by the combination of local density approximation and dynamical mean-field theory (2008)
  • Author(s): R. Arita, K. Kuroki, K. Held, A. V. Lukoyanov, S. Skornyakov, V. I. Anisimov
  • Journal Title: Physical Review B 78 Pages: 115121-1-5
  • Peer Reviewed
• [Journal Article] Electronic Structure and Electron Correlation in LaFeAsO_<1-x>F_x and LaFePO_<1-x>F_x (2008)
  • Author(s): W. Malaeb, T. Yoshida, T. Kataoka, A. Fujimori, M. Kubota, K. Ono, H. Usui, K. Kuroki, R, Arita, H. Aoki, Y. Kamihara, M. Hirano, H. Hosono
  • Journal Title: J. Phys. Soc. Jpn. 77 Pages: 093714-1-4
  • Peer Reviewed
• [Presentation] Spin fluctuation mediated extended s-wave pairing from multiple Fermi surfaces in iron pnictide superconductors (2009)
  • Author(s): 黒木和彦
  • Organizer: American Physical Society, March Meeting
  • Place of Presentation: Pittsburgh, USA
  • Year and Date: 20090316-20090320
• [Presentation] ペロプスガイド型遷移金属酸化物における熱起電力の第一原理計算による解析 (2009)
  • Author(s): 臼井秀知
  • Organizer: 日本物理学会第64回年次大会
  • Place of Presentation: 立教大学
  • Year and Date: 2009-03-30
• [Presentation] 層状窒化物超伝導体MNCl(M=Hf, Zr)におけるスピン揺らぎペアリング機構 (2009)
  • Author(s): 黒木和彦
  • Organizer: 日本物理学会第64回年次大会
  • Place of Presentation: 立教大学
  • Year and Date: 2009-03-30
• [Presentation] Peculiar band structures as origin of the large thermopower in Cobalt and Rhodium oxides (2008)
  • Author(s): 黒木和彦
  • Organizer: 2nd International Symposium on Anomalous Quantum Materials
  • Place of Presentation: 東京大学
  • Year and Date: 20081107-20081110
• [Presentation] Unconventional Pairing in Doped Band Insulators on a Honeycomb Lattice : Application to Superconducting β-MNC1 (M=Hf, Zr) (2008)
  • Author(s): K. Kuroki
  • Organizer: 25th Int. Conf. Low Temp. Phys.
  • Place of Presentation: Amsterdam, Netherlands
  • Year and Date: 20080806-20080813
• [Presentation] An improved alogorithm for the functional renormalization group and its application to the 2D Hubbard model (2008)
  • Author(s): H. Takashima
  • Organizer: 25th Int. Conf. Low Temp. Phys.
  • Place of Presentation: Amsterdam, Netherlands
  • Year and Date: 20080806-20080813
• [Presentation] Minimal Model for Study on Superconductivity in LaFeAsO_<1-x>F_x (2008)
  • Author(s): K. Kuroki
  • Organizer: 25th Int. Conf. Low Temp. Phys.
  • Place of Presentation: Amsterdam, Netherlands
  • Year and Date: 20080806-20080813
• [Presentation] Study on the origin of large thermopower in hole doped LaRhO_3 based on ab-initio downfolding (2008)
  • Author(s): H. Usui
  • Organizer: 25th Int. Conf. Low Temp. Phys.
  • Place of Presentation: Amsterdam, Netherlands
  • Year and Date: 20080806-20080813
• [Presentation] Competition between triplet, singlet and FFLO states in organic superconductors (TMTSF)_2X under magnetic field (2008)
  • Author(s): H. Aizawa
  • Organizer: 25th Int. Conf. Low Temp. Phys.
  • Place of Presentation: Amsterdam, Netherlands
  • Year and Date: 20080806-20080813
• [Presentation] First-principles study on the origin of large thermopower in hole-doped LaRhO_3 and CuRhO_2 (2008)
  • Author(s): H. Usui
  • Organizer: 2nd Int. Workshop on Quantum Simulations and Designings
  • Place of Presentation: 東京、科学未来館
  • Year and Date: 20080531-20080603
• [Presentation] 特異なバンド形状が生み出す大きな熱起電力 (2008)
  • Author(s): 黒木和彦
  • Organizer: 研究会 : 新しい概念に基づく熱電材料とその物理
  • Place of Presentation: 東北大学金属材料研究所
  • Year and Date: 2008-12-12
• [Presentation] 静的近似を超えた汎関数繰り込み群法と2次元Hubbard模型への適用 (2008)
  • Author(s): 高島宏和
  • Organizer: 日本物理学会2008年秋季大会
  • Place of Presentation: 岩手大学
  • Year and Date: 2008-09-22
• [Presentation] スピン揺らぎ媒介超伝導のFFLO状態におけるトリプレット対成分混合の効果 (2008)
  • Author(s): 相澤啓仁
  • Organizer: 日本物理学会2008年秋季大会
  • Place of Presentation: 岩手大学
  • Year and Date: 2008-09-22
• [Presentation] 鉄砒素系超伝導体の有効模型とペアリング・メカニズム (2008)
  • Author(s): 黒木和彦
  • Organizer: 日本物理学会2008年秋季大会
  • Place of Presentation: 岩手大学
  • Year and Date: 2008-09-21
• [Presentation] 第一原理計算に基づくLaRhO_3の高い熱起電力の研究 : 最局在ワニエ基底による解析 (2008)
  • Author(s): 臼井秀知
  • Organizer: 日本物理学会2008年秋季大会
  • Place of Presentation: 岩手大学
  • Year and Date: 2008-09-21
• [Book] 熱電変換技術ハンドブック(第2章、3-6節) (2008)
  • Author(s): 黒木和彦
  • Total Pages: 237-248
  • Publisher: NTS
• [Remarks]
  • URL: http://www.e-one.uec.ac.jp/~kuroki/