Study of superconducting symmetry and anomalous metallic state in pressure-induced unconventional superconductors

2010 Fiscal Year Final Research Report

• Project/Area Number: 20684016
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Condensed matter physics II
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: IZAWA Koichi Tokyo Institute of Technology, 大学院・理工学研究科, 准教授 (90302637)
• Project Period (FY): 2008 – 2010
• Keywords: 超伝導・密度波 / 超伝導対称性 / 量子臨界性

Research Abstract

In order to understand superconducting symmetry and anomalous metallic state of unconventional superconductors, we studied the low-energy excitation of quasi-particles (QPs) by the thermal transport and specific heat measurements. As the results, we clarified the low energy QP excitation structure of iron pnictides, d-electron multi-gap superconductor, β-pyrochlore superconductor, and multicomponent superconductor. We also get new information on the quantum criticality in the anomalous metallic state of Yb compounds.

Research Products

• [Journal Article] Enhanced quasiparticle heat conduction of the multigap superconductor Lu_2Fe_3Si_5 (2011)
  • Author(s): Y.Machida, S.Sakai, K.Izawa, H.Okuyama, T.Watanabe
  • Journal Title: Phys Rev.Lett. 106 Pages: 107002-1-107002-4
  • Peer Reviewed
• [Journal Article] Low-temperature thermal transport coefficients of heavy fermion β-YbAlB_4 (2011)
  • Author(s): Y.Machida, C.Ogura, K.Izawa, K.Kuga, S.Nakatsuji
  • Journal Title: Journal of Physics : Conference Series 273 Pages: 012005-1-012005-4
  • Peer Reviewed
• [Journal Article] Pressure effect on the superconductivity of β-pyrochlore oxides (2011)
  • Author(s): T.Isono, D.Iguchi, Y.Machida, K.Izawa, B.Salce, J.Flouquet, H.Ogusu, J.Yamaura, Z.Hiroi
  • Journal Title: Journal of Physics : Conference Series 273 Pages: 012076-1-012076-4
  • Peer Reviewed
• [Journal Article] Thermal conductivity tensor of single crystalline Co-doped BaFe_2As_2 (2011)
  • Author(s): Y.Machida, K.Tomokuni, T.Isono, K.Izawa, Y.Nakajima, T.Tamegai
  • Journal Title: Physica E 43 Pages: 714-717
  • Peer Reviewed
• [Journal Article] Low-temperature specific heat of the β-pyrochlore oxide superconductors under high pressure (2011)
  • Author(s): T.Isono, D.Iguchi, Y.Machida, K.Izawa, B.Salce, J.Flouquet, H.Ogusu, J.Yamaura, Z.Hiroi
  • Journal Title: Physica E 43 Pages: 726-729
  • Peer Reviewed
• [Journal Article] Thermal transport studies on Co-doped BaFe_2As_2 (2010)
  • Author(s): Y.Machida, K.Tomokuni, T.Isono, K.Izawa, Y.Nakajima, T.Tamegai
  • Journal Title: Physica C 470 Pages: S478-S479
  • Peer Reviewed
• [Journal Article] Low temperature specific heat of the β-pyrochlore superconductors under high pressure (2010)
  • Author(s): T.Isono, D.Iguchi, Y.Machida, K.Izawa, B.Salce, J.Flouquet, H.Ogusu, J.Yamaura, Z.Hiroi
  • Journal Title: Physica C 470 Pages: S721-S722
  • Peer Reviewed
• [Journal Article] Possible Sign-Reversing s-Wave Superconductivity in Co-Doped BaFe_2As_2 Proved by Thermal Transport Measurements (2009)
  • Author(s): Y.Machida, K.Tomokuni, T.Isono, K Izawa, Y.Nakajima, T.Tamegai
  • Journal Title: J.Phys.Soc.Jpn. 78 Pages: 073705-1-073705-4
  • Peer Reviewed
• [Journal Article] Re-examination of the crystal structure of the beta-pyrochlore oxide superconductor KOs_2O_6 by X-ray and convergent-beam electron diffraction analyses (2009)
  • Author(s): JI.Yamaura, Z.Hiroi, K.Tsuda, K.Izawa, Y.Ohishi, S.Tsutsui
  • Journal Title: Solid State Communications 149 Pages: 31-34
  • Peer Reviewed
• [Journal Article] Non-Fermi liquid behavior in the magnetotransport of quasi two-dimensional heavy Fermion compounds CeMIn_5 (2008)
  • Author(s): Y Nakajima, T.Shibauchi, H.Shishido, H.Nakai, K.Behnia, K.Izawa, M.Hedo, Y.Uwatoko, T.Matsumoto, R.Settai, Y.Onuki, H.Kontani, Y.Matsuda
  • Journal Title: Journal of Physics and Chemistry of Solids 69 Pages: 3261-3264
  • Peer Reviewed
• [Journal Article] Transport anomalies across the quantum limit in semimetallic Bi_<0.96>Sb_<0.04> (2008)
  • Author(s): A.Banerjee, B.Fauque, K.Izawa, A.Miyake, I.Sheikin, J.Flouquet, B.Lenoir, K.Behnia
  • Journal Title: Phys.Rev.B 78 Pages: 161103-1-161103-4
  • Peer Reviewed
• [Presentation] 熱伝導率でみたUPt_3の超伝導ギャップ構造 (2011)
  • Author(s): 町田洋, 伊藤淳史, 宗義尚, 井澤公一, 芳賀芳範, 山本悦嗣, 木村憲彰, 大貫惇睦
  • Organizer: 日本物理学会第66回年次大会
  • Place of Presentation: 新潟大学
  • Year and Date: 2011-03-25
• [Presentation] Thermoelectric coefficients of the quantum critical β-YbAlB_4 (2010)
  • Author(s): Y.Machida, C.Ogura, K.Izawa, K.Kuga, S.Nakatsuji
  • Organizer: International Conference on Heavy Electrons 2010
  • Place of Presentation: Tokyo
  • Year and Date: 20100917-20100920
• [Presentation] Pressure dependence of upper critical field in β-pyrochlore oxides (2010)
  • Author(s): D.Iguchi, T.Isono, Y.Machida, K.Izawa, B.Salce, J.Flouquet, H.Ogusu, J.-I.Yamaura, Z.Hiroi
  • Organizer: International Conference on Heavy Electrons 2010
  • Place of Presentation: Tokyo
  • Year and Date: 20100917-20100920
• [Presentation] Crystal structure and superconductivity of β-pyrochlore oxides under high pressure (2010)
  • Author(s): T.Isono, D.Iguchi, Y.Machida, K.Izawa, B.Salce, J.Flouquet, H.Ogusu, J.-I.Yamaura, Z.Hiroi
  • Organizer: International Conference on Heavy Electrons 2010
  • Place of Presentation: Tokyo
  • Year and Date: 20100917-20100920
• [Presentation] Thermal transport properties and quantum criticality of heavy fermion YbRh_2Si_2 (2010)
  • Author(s): K.Tomokuni, Y.Machida, K.Izawa, G.Lapertot, G.Knebel, J-P.Brison, J.Flouquet
  • Organizer: International Conference on Heavy Electrons 2010
  • Place of Presentation: Tokyo
  • Year and Date: 20100917-20100920
• [Presentation] Quantum criticality of YbRh_2Si_2 and related compounds studied by thermal conductivity and thermoelectric coefficients (2010)
  • Author(s): K.Izawa, K.Tomokuni, Y.Machida, G.Lapertot, G.Knebel, J.- P.Brison, J.Flouquet
  • Organizer: The 2010 International Conference on Strongly Correlated Electron Systems
  • Place of Presentation: Santa Fe, NM, USA
  • Year and Date: 20100627-20100702
• [Presentation] Low-temperature thermal transport coefficients of heavy fermion β-YbAlB_4 (2010)
  • Author(s): Y.Machida, C.Ogura, K.Izawa, K.Kuga, S.Nakatsuji
  • Organizer: The 2010 International Conference on Strongly Correlated Electron Systems
  • Place of Presentation: Santa Fe, NM, USA
  • Year and Date: 20100627-20100702
• [Presentation] Pressure effect on the superconductivity of β-pyrochlore oxides (2010)
  • Author(s): T.Isono, D.Iguchi, Y.Machida, K.Izawa, B.Salce, J.Flouquet, H.Ogusu, J.-I.Yamaura, Z.Hiroi
  • Organizer: The 2010 International Conference on Strongly Correlated Electron Systems
  • Place of Presentation: Santa Fe, NM, USA
  • Year and Date: 20100627-20100702
• [Presentation] Probing quantum criticality in strongly correlated electron systems by transport coefficients (2010)
  • Author(s): K.Izawa
  • Organizer: International Workshop : The New Generation in Strongly Correlated Electron Systems 2010
  • Place of Presentation: Lanzarote, Spain
  • Year and Date: 20100620-20100625
• [Presentation] β型ハイロクロア酸化物の圧力下における結晶構造と超伝導特性 (2010)
  • Author(s): 磯野貴之, 原悠太, 井口大輔, 町田洋, 井澤公一, 筒井智嗣, 大石泰生, B.Salce, J.Flouquet, 小楠寛貴, 山浦淳一, 広井善二
  • Organizer: 日本物理学会第65回秋季大会
  • Place of Presentation: 大阪府立大学中百舌鳥キャンパス
  • Year and Date: 2010-09-25
• [Presentation] 熱伝導率からみた重い電子系β-YbAlB_4の量子臨界性 (2010)
  • Author(s): 町田洋, 小椋千花子, 井澤公一, 久我健太郎, 中辻知
  • Organizer: 日本物理学会第65回秋季大会
  • Place of Presentation: 大阪府立大学中百舌鳥キャンパス
  • Year and Date: 2010-09-23
• [Presentation] 重い電子系化合物YbRh_2Si_2の熱電係数と量子臨界性 (2010)
  • Author(s): 友國恒介, 町田洋, 井澤公一, G.Lapertot, G.Knebel, J-P.Brison, J.Flouquet
  • Organizer: 日本物理学会第65回秋季大会
  • Place of Presentation: 大阪府立大学中百舌鳥キャンパス
  • Year and Date: 2010-09-23
• [Presentation] 重い電子系β-YbAlB_4の低温熱輸送係数 (2010)
  • Author(s): 町田洋, 小椋千花子, 井澤公一, 久我健太郎, 中辻知
  • Organizer: 日本物理学会第65回年次大会
  • Place of Presentation: 岡山大学
  • Year and Date: 2010-03-21
• [Presentation] 重い電子系化合物YbRh_2Si_2の量子臨界点近傍における熱輸送特性 (2010)
  • Author(s): 友國恒介, 町田洋, 井澤公一, G.Lapertot, J-P.Brison, J.Flouquet
  • Organizer: 日本物理学会第65回年次大会
  • Place of Presentation: 岡山大学
  • Year and Date: 2010-03-21
• [Presentation] β型パイロクロア酸化物RbOs_2O_6の上部臨界磁場の圧力依存性 (2010)
  • Author(s): 井口大輔, 磯野貴之, 町田洋, 井澤公一, 小楠寛貴, 山浦淳一, 廣井善二
  • Organizer: 日本物理学会第65回年次大会
  • Place of Presentation: 岡山大学
  • Year and Date: 2010-03-21
• [Presentation] 熱伝導率でみたマルチギャップ超伝導体Lu_2Fe_3Si_5の準粒子低エネルギー励起 (2010)
  • Author(s): 酒井翔, 町田洋, 井澤公一, 渡辺忠孝, 奥山浩朗
  • Organizer: 日本物理学会第65回年次大会
  • Place of Presentation: 岡山大学
  • Year and Date: 2010-03-20
• [Presentation] Thermal Transport Studies on Co-doped BaFe_2As_2 (2009)
  • Author(s): Y.Machida, K.Tomokuni, K.Izawa, Y.Nakajima, T.Tamegai
  • Organizer: 9th Interna- tional Conference on Materials and Mechanisms of Superconductivity
  • Place of Presentation: Tokyo
  • Year and Date: 20090207-20090212
• [Presentation] Low Temperature Specific Heat of the beta-Pyrochlore Superconduc-tors under High Pressure (2009)
  • Author(s): T.Isono, D.Iguchi, Y.Machida, K.Izawa, B.Sales, J.Flouquet, J.Yamaura, Z.Hiroi
  • Organizer: 9th Interna- tional Conference on Materials and Mechanisms of Superconductivity
  • Place of Presentation: Tokyo
  • Year and Date: 20090207-20090212
• [Presentation] 鉄珪化物超伝導体Lu_2Fe_3Si_5の熱伝導率 (2009)
  • Author(s): 町田洋, 酒井翔, 井澤公一, 渡辺忠孝, 奥山浩朗
  • Organizer: 日本物理学会2009年秋季大会
  • Place of Presentation: 熊本大学
  • Year and Date: 2009-09-28
• [Presentation] 熱輸送係数測定によるβ-YbAlB_4の量子臨界性 (2009)
  • Author(s): 小椋千花子, 町田洋, 井澤公一, 久我健太郎, 冨田崇弘, 中辻 知
  • Organizer: 日本物理学会2009年秋季大会
  • Place of Presentation: 熊本大学
  • Year and Date: 2009-09-28
• [Presentation] β型パイロクロア酸化物超伝導体の高圧下における低温比熱 (2009)
  • Author(s): 磯野貴之, 井口大輔, 町田洋, 井澤公一, B.Salce, J.Flouquet, 小楠寛貴, 山浦淳一, 広井善二
  • Organizer: 日本物理学会2009年秋季大会
  • Place of Presentation: 熊本大学
  • Year and Date: 2009-09-27
• [Presentation] 鉄砒素系超伝導体Ba(Fe_<1-x>Co_x)_2As_2の熱伝導率 (2009)
  • Author(s): 町田洋, 友國恒介, 磯野貴之, 井澤公一, 仲島康行, 為ヶ井強
  • Organizer: 日本物理学会第64回年次大会
  • Place of Presentation: 立教大学
  • Year and Date: 2009-03-27
• [Presentation] 強磁場下におけるSrCu_2(BO_3)_2の異常な熱輸送 (2008)
  • Author(s): 井澤公一, K.Behnia, I.Sheikin, 陰山洋, J.Flouquet
  • Organizer: 日本物理学会2008年秋季大会
  • Place of Presentation: 岩手大学
  • Year and Date: 2008-09-20