Updated on 2022/07/02

写真a

 
MATANO Kazuaki
 
Organization
Faculty of Natural Science and Technology Assistant Professor
Position
Assistant Professor
External link

Degree

  • 博士(理学) ( 岡山大学 )

Research Interests

  • condensed matter physics

  • 物性物理学

  • 核磁気共鳴

  • 超伝導

  • トポロジカル物質

Research Areas

  • Natural Science / Magnetism, superconductivity and strongly correlated systems

Education

  • 岡山大学 大学院   自然科学研究科  

    2007.4 - 2009.3

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    Notes: 早期修了

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  • 岡山大学 大学院   自然科学研究科  

    2005.4 - 2007.3

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  • Okayama University   理学部   物理学科

    2001.4 - 2005.3

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Research History

  • Okayama University   The Graduate School of Natural Science and Technology   Assistant Professor

    2012.2

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    Country:Japan

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  • Okayama University   The Graduate School of Natural Science and Technology

    2010 - 2012

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    Country:Japan

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  • NEC Corporation

    2009.4 - 2010.9

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    Country:Japan

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  • Japan Society for the Promotion of Science

    2007.4 - 2009.3

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    Country:Japan

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Professional Memberships

 

Papers

  • Antiferromagnetic spin fluctuations and superconductivity in NbRh2B2 and TaRh2B2 with a chiral crystal structure Reviewed International coauthorship International journal

    Kazuaki Matano, Ryo Ogura, Mateo Fountaine, Harald O. Jeschke, Shinji Kawasaki, Guo-qing Zheng

    Physical Review B   104 ( 22 )   224508-1 - 224508-8   2021.12

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society (APS)  

    DOI: 10.1103/physrevb.104.224508

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    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.104.224508/fulltext

  • Localized-to-itinerant transition preceding antiferromagnetic quantum critical point and gapless superconductivity in CeRh0.5Ir0.5In5 Reviewed International coauthorship International journal

    Shinji Kawasaki, Toshihide Oka, Akira Sorime, Yuji Kogame, Kazuhiro Uemoto, Kazuaki Matano, Jing Guo, Shu Cai, Liling Sun, John L. Sarrao, Joe D. Thompson, Guo-qing Zheng

    Communications Physics   3 ( 1 )   1 - 10   2020.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1038/s42005-020-00418-x

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    Other Link: http://www.nature.com/articles/s42005-020-00418-x

  • Landau diamagnetism and Weyl-fermion excitations in TaAs revealed by As75 NMR and NQR Reviewed International coauthorship International journal

    C. G. Wang, Yoshiaki Honjo, L. X. Zhao, G. F. Chen, K. Matano, R. Zhou, Guo-qing Zheng

    Physical Review B Rapid Communication   101 ( 24 )   241110-1 - 241110-6   2020.6

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    DOI: 10.1103/physrevb.101.241110

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    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.101.241110/fulltext

  • NMR and NQR studies on transition-metal arsenide superconductors LaRu2As2, KCa2Fe4As4F2, and A 2Cr3As3 International coauthorship International journal

    Jun Luo, Chunguang Wang, Zhicheng Wang, Qi Guo, Ji Yang, Rui Zhou, K Matano, T Oguchi, Zhian Ren, Guanghan Cao, Guo-Qing Zheng

    Chinese Physics B   29 ( 6 )   067402 - 067402   2020.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP Publishing  

    DOI: 10.1088/1674-1056/ab892d

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    Other Link: https://iopscience.iop.org/article/10.1088/1674-1056/ab892d/pdf

  • Direction and symmetry transition of the vector order parameter in topological superconductors CuxBi2Se3 Reviewed International coauthorship International journal

    T. Kawai, C. G. Wang, Y. Kandori, Y. Honoki, K. Matano, T. Kambe, Guo-qing Zheng

    Nature Communications   11 ( 1 )   1 - 7   2020.1

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    DOI: 10.1038/s41467-019-14126-w

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    Other Link: http://www.nature.com/articles/s41467-019-14126-w

  • Fully gapped spin-singlet superconductivity in noncentrosymmetric PbTaSe2: Pb-207 nuclear magnetic resonance study Reviewed International coauthorship International journal

    S. Maeda, K. Matano, Guo-qing Zheng

    Physical Review B   97 ( 18 )   184510-1 - 184510-5   2018.5

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    We report the Pb-207 nuclear magnetic resonance (NMR) measurements on polycrystalline sample of PbTaSe2 with noncentrosymmetric crystal structure and topological electronic band. The nuclear spin-lattice relaxation rate 1 / T-1) shows a suppressed coherence peak below the superconducting transition temperature T-c = 4.05 K and decreases as an exponential function of temperature. The penetration depth derived from the NMR spectrum is almost temperature independent below T = 0.7 T-c. The Knight shift K decreases below T-c. These results suggest spin-singlet superconductivity with a fully opened gap 2 Delta = 3.5 k(B)T(c) in PbTaSe2.

    DOI: 10.1103/PhysRevB.97.184510

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  • Spin-Triplet Nematic Superconductivity in CuxBi2Se3 Reviewed

    Kazuaki Matano, Shingo Yonezawa

    73 ( 2 )   103 - 108   2018.2

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    Authorship:Lead author   Language:Japanese   Publishing type:Research paper (other academic)  

    DOI: 10.11316/butsuri.73.2_103

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  • Spin-singlet superconductivity in the doped topological crystalline insulator Sn0.96In0.04Te Reviewed International coauthorship

    Satoki Maeda, Ryohei Hirose, Kazuaki Matano, Mario Novak, Yoichi Ando, Guo-qing Zheng

    Physical Review B   96 ( 10 )   104502-1 - 104502-5   2017.9

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    The In-doped topological crystalline insulator Sn1-x In-x Te is a candidate for a topological superconductor, where a pseudo-spin-triplet state has been proposed. To clarify the spin symmetry of Sn1-x In-x Te, we perform Te-125-nuclear magnetic resonance (NMR) measurements in polycrystalline samples with 0 <= x <= 0.15. The penetration depth calculated from the NMR line width is T independent below half the superconducting transition temperature (T-c) in polycrystalline Sn0.96In0.04Te, which indicates a fully opened superconducting gap. In this sample, the spin susceptibility measured by the spin Knight shift (K-s) at an external magnetic field of H-mu 0(0) = 0.0872 T decreases below T-c, and K-s(T = 0)/K-s(T = T-c) reaches 0.36 +/- 0.10, which is far below the limiting value 2/3 expected for a spin-triplet state for a cubic crystal structure. Our result indicates that polycrystalline Sn0.96In0.04Te is a spin-singlet superconductor.

    DOI: 10.1103/PhysRevB.96.104502

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  • Full-gap superconductivity in noncentrosymmetric Re6Zr, Re27Zr5, and Re24Zr5 Reviewed

    K. Matano, R. Yatagai, S. Maeda, Guo-qing Zheng

    Physical Review B   94 ( 21 )   214513-1 - 214513-5   2016.12

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    The noncentrosymmetric superconductor Re6Zr has attracted much interest for its possible unconventional superconducting state with broken time-reversal symmetry. Here we report Re-185/187 nuclear quadrupole resonance measurements on Re6Zr (T-c = 6.72 K) and the isostructural compounds Re27Zr5 (T-c = 6.53 K) and Re24Zr5 (T-c = 5.00 K). The nuclear spin-lattice relaxation rate 1/T-1 shows a coherence peak below T-c and decreases exponentially at low temperatures in all three samples. The superconducting gap Delta derived from the 1/T-1 data is 2 Delta = 3.58k(B)T(c), 3.55k(B)T(c), and 3.51k(B)T(c) for Re6Zr, Re27Zr5, and Re24Zr5, respectively, which is close to the value of 3.53k(B)T(c) expected for weak-coupling superconductivity. These data suggest conventional s-wave superconductivity with a fully opened gap in this series of compounds.

    DOI: 10.1103/PhysRevB.94.214513

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  • Spin-rotation symmetry breaking in the superconducting state of CuxBi2Se3 Reviewed

    K. Matano, M. Kriener, K. Segawa, Y. Ando, Guo-qing Zheng

    Nature Physics   12 ( 9 )   852 - 854   2016.5

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:NATURE PUBLISHING GROUP  

    Spontaneous symmetry breaking is an important concept for understanding physics ranging from the elementary particles to states of matter. For example, the superconducting state breaks global gauge symmetry, and unconventional superconductors can break further symmetries. In particular, spin-rotational symmetry is expected to be broken in spin triplet superconductors. However, experimental evidence for such symmetry breaking has not been conclusively obtained so far in any candidate compounds. Here, using Se-77 nuclear magnetic resonance measurements, we show that spin-rotation symmetry is spontaneously broken in the hexagonal plane of the electron-doped topological insulator Cu0.3Bi2Se3 below the superconducting transition temperature T-c = 3.4 K. Our results not only establish spin-triplet superconductivity in this compound, but may also serve to lay a foundation for the research of topological superconductivity.

    DOI: 10.1038/NPHYS3781

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  • 19aBN-9 NMR/NQR studies of the non-centrosymmetric superconductor

    Yatagai R., Mori H., Maeda S., Matano K., Zheng G.-q.

    Meeting Abstracts of the Physical Society of Japan   71   1985 - 1985   2016

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    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    DOI: 10.11316/jpsgaiyo.71.1.0_1985

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  • Superconductivity and the electronic phase diagram of LaPt2-xGe2+x Reviewed

    S. Maeda, K. Matano, R. Yatagai, T. Oguchi, Guo-Qing Zheng

    Physical Review B - Condensed Matter and Materials Physics   91 ( 17 )   2015.5

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    In many cases, unconventional superconductivity are realized by suppressing another order parameter, such as charge density wave (CDW) or spin density wave (SDW). This suggests that the fluctuations of these order parameters play an important role in producing superconductivity. LaPt2Ge2 undergoes a tetragonal-to-monoclinic structural phase transition (SPT) at Ts=394 K, accompanying a double period modulation in the a-axis direction, and superconducts at Tc=0.41 K. We performed band calculations and found 2D (two dimensional)-like Fermi surfaces with partial nesting. A reduction in the density of states in the monoclinic phase was found in the calculation and confirmed by Pt195-NMR. We suggest a CDW as a possible cause for the SPT. By changing the stoichiometry between Pt and Ge, we succeeded in suppressing Ts and increasing Tc in LaPt2-xGe2+x. Comparison of La139- and Pt195-NMR data reveals moderate fluctuations associated with SPT. From La139-NQR measurements at zero field, we found that an isotropic superconducting gap is realized in LaPt2-xGe2+x (x=0.20). We discuss the relationship between superconductivity and the SPT order/fluctuations.

    DOI: 10.1103/PhysRevB.91.174516

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  • Superconductivity and the electronic phase diagram of LaPt2-xGe2+x Reviewed

    S. Maeda, K. Matano, R. Yatagai, T. Oguchi, Guo-qing Zheng

    Physical Review B   91 ( 17 )   174516-1 - 174516-7   2015.5

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    In many cases, unconventional superconductivity are realized by suppressing another order parameter, such as charge density wave (CDW) or spin density wave (SDW). This suggests that the fluctuations of these order parameters play an important role in producing superconductivity. LaPt2Ge2 undergoes a tetragonal-to-monoclinic structural phase transition (SPT) at T-s = 394 K, accompanying a double period modulation in the a-axis direction, and superconducts at T-c = 0.41 K. We performed band calculations and found 2D (two dimensional)-like Fermi surfaces with partial nesting. A reduction in the density of states in the monoclinic phase was found in the calculation and confirmed by Pt-195-NMR. We suggest a CDW as a possible cause for the SPT. By changing the stoichiometry between Pt and Ge, we succeeded in suppressing T-s and increasing T-c in LaPt2-xGe2+x. Comparison of La-139- and Pt-195-NMR data reveals moderate fluctuations associated with SPT. From La-139-NQR measurements at zero field, we found that an isotropic superconducting gap is realized in LaPt2-xGe2+x (x = 0.20). We discuss the relationship between superconductivity and the SPT order/fluctuations.

    DOI: 10.1103/PhysRevB.91.174516

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  • Spin-singlet superconductivity with a full gap in locally noncentrosymmetric SrPtAs Reviewed

    K. Matano, K. Arima, S. Maeda, Y. Nishikubo, K. Kudo, M. Nohara, Guo-qing Zheng

    Physical Review B Rapid Communication   89 ( 14 )   140504-1 - 140504-4   2014.4

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    We report Pt-195-NMR and As-75 nuclear quadrupole resonance measurements for the locally noncentrosymmetric superconductor SrPtAs where the As-Pt layer breaks inversion symmetry while globally the compound is centrosymmetric. The nuclear spin-lattice relaxation rate 1/T-1 shows a well-defined coherence peak below T-c and decreases exponentially at low temperatures. The spin susceptibility measured by the Knight shift also decreases below Tc down to T < T-c/6. These data, together with the penetration depth obtained from the NMR spectra, can be consistently explained by a spin-singlet superconducting state with a full gap. Our results suggest that the spin-orbit coupling due to the local inversion-symmetry breaking is not large enough to bring about an exotic superconducting state, or the interlayer hopping interaction is larger than the spin-orbit coupling.

    DOI: 10.1103/PhysRevB.89.140504

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  • NMR and NQR Studies on Non-centrosymmetric Superconductors Re7B3, LaBiPt, and BiPd Reviewed

    Kazuaki Matano, Satoki Maeda, Hiroki Sawaoka, Yuji Muro, Toshiro Takabatake, Bhanu Joshi, Srinivasan Ramakrishnan, Kenji Kawashima, Jun Akimitsu, Guo-qing Zheng

    Journal of the Physical Society of Japan   82 ( 8 )   084711-1 - 084711-5   2013.5

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We report the nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements for non-centrosymmetric superconductors Re7B3, LaBiPt, and BiPd containing heavy elements. For all three compounds, the spin-lattice relaxation rate 1/T-1 shows a coherence peak just below T-c and decreases exponentially at low temperatures, which indicates that an isotropic superconducting gap is dominant in these compounds. In BiPd, the height of the coherence peak just below T-c is much suppressed, which suggests that there exists a substantial component of gap with nodes in this compound. Our results indicate that heavy element is not the only factor, but the extent of inversion symmetry breaking is also important to induce a large spin-orbit coupling and an unconventional superconducting state.

    DOI: 10.7566/JPSJ.82.084711

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  • Superconductivity in Tetragonal LaPt2-xGe2+x Reviewed

    Satoki Maeda, Kazuaki Matano, Hiroki Sawaoka, Yoshihiko Inada, Guo-qing Zheng

    Journal of the Physical Society of Japan   82 ( 6 )   065002 -1 - 065002 -2   2013.3

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    DOI: 10.7566/JPSJ.82.065002

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  • NMR study of the impurity effects in noncentrosymmetric superconductors Li-2(Pd,Pt)(3)B Reviewed

    K. Arima, K. Matano, S. Harada, G. Z. Bao, Y. Inada, G. Q. Zheng

    10th International Conference on Materials and Mechanisms of Superconductivity (M2S-X)   449   012034-1 - 012034-3   2013

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    We report B-11 nuclear magnetic resonance (NMR) studies of the impurity effect in noncentrosymmetric superconductors Li2Pt3B and Li2Pd3B. We substitute B with Al, and find that the full width of half maximum (FWHM) of the NMR spectrum increases with increasing Al content. The superconducting transition temperature (T-c) of Li2Pt3 B1-xAlx decreases drastically with increasing non-magnetic impurity (Al) content, while it is hardly affected in Li2Pd3 B(1-x)A(l)x. These results provide new evidence for superconducting gap with line nodes in Li2Pt3B.

    DOI: 10.1088/1742-6596/449/1/012034

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  • Multiple Superconducting Gaps and Anisotropic Spin Fluctuations in Hole-Doped and Electron-Doped Iron-Pnictides: NMR Studies Reviewed

    Guo-qing Zheng, K. Matano, S. Kawasaki, Z. Li, G. L. Sun, D. L. Sun, C. T. Lin, G. F. Chen, J. L. Luo, N. L. Wang, Z. A. Ren, Z. X. Zhao

    Journal of Superconductivity and Novel Magnetism   23 ( 5 )   609 - 612   2010.1

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    We present extensive As-75-NMR data on the electron-doped pnictides PrFeAsO0.89F0.11 (T-c = 45 K), LaFeAsO0.92F0.08 (T-c = 23 K), and the hole-doped Ba0.72K0.28Fe2As2 (T-c = 31.5 K) single crystal. We find that the Fe antiferromagnetic spin fluctuations are anisotropic and are weaker compared to underdoped copper-oxides or cobalt-oxide superconductors. The spin lattice relaxation rate 1 / T-1 decreases below T-c with no coherence peak and shows a step-wise variation at low temperatures. The Knight shift decreases below T-c and shows a step-wise T variation as well. These results indicate spin-singlet superconductivity with multiple gaps.

    DOI: 10.1007/s10948-010-0749-1

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  • As-75 NMR studies of superconducting Ba0.72K0.28Fe2As2 Reviewed

    Z. Li, K. Matano, D. L. Sun, G. L. Sun, C. T. Lin, M. Ichioka, G. -Q. Zheng

    Physica C: Superconductivity and its Applications   470   S495 - S496   2009.12

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    We have performed As-75 nuclear magnetic resonance measurements on a single crystal of the hole-doped superconductor Ba0.72K0.28Fe2As2 (T-c = 31.5 K). The spin-lattice relaxation rate 1/T-1 decreases below T-c with no coherence peak and shows a step-wise variation at low temperatures, which is indicative of multiple superconducting gaps. In the normal state, we find that Fe antiferromagnetic spin fluctuations are anisotropic. (C) 2009 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physc.2009.11.174

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  • Anisotropic spin fluctuations and multiple superconducting gaps in hole-doped Ba0.72K0.28Fe2As2: NMR in a single crystal Reviewed

    K. Matano, Z. Li, G. L. Sun, D. L. Sun, C. T. Lin, M. Ichioka, Guo-Qing Zheng

    Europhysics Letters   87 ( 2 )   27012-p1 - 27012-p6   2009.8

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    We report the As-75-NMR study on a single crystal of the hole-doped iron-pnictide superconductor Ba0.72K0.28Fe2As2 (T-c = 31.5 K). We find that the Fe antiferromagnetic spin fluctuations are anisotropic and are weaker compared to underdoped copper-oxides or cobalt-oxide superconductors. The spin lattice relaxation rate 1/T-1 decreases below T-c with no coherence peak and shows a stepwise variation at low temperatures, which is indicative of multiple superconducting gaps, as in the electron-doped Pr(La) FeAsO1-xFx. Furthermore, no evidence was obtained for a microscopic coexistence of a long-range magnetic order and superconductivity. Copyright (C) EPLA, 2009

    DOI: 10.1209/0295-5075/87/27012

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  • Hydration-induced anisotropic spin fluctuations in NaxCoO2 center dot 1.3H(2)O superconductor Reviewed

    K. Matano, C. T. Lin, Guo-qing Zheng

    Europhysics Letters   84 ( 5 )   57010-p1 - 57010-p5   2008.12

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:EPL ASSOCIATION, EUROPEAN PHYSICAL SOCIETY  

    We report Co-59 NMR studies in single crystals of the cobalt oxide superconductor Na0.42CoO2 center dot 1.3H(2)O (T-c = 4.25 K) and its parent compound Na0.42CoO2. We find that both the magnitude and the temperature (T) dependence of the Knight shifts are identical in the two compounds above T-c. The spin-lattice relaxation rate (1/T-1) is also identical above T-0 similar to 60K for both compounds. Below T-0, the unhydrated sample is found to be a non-correlated metal that well conforms to the Fermi liquid theory, while spin fluctuations develop in the superconductor. These results indicate that water intercalation does not change the density of states at the Fermi level or the carrier density but its primary role is to bring about spin fluctuations. Our result shows that, in the hydrated superconducting compound, the electron correlation is anisotropic. Namely, the spin fluctuation around the finite wave vector is much stronger along the a-axis direction than that along the c-axis direction. Copyright (C) EPLA, 2008

    DOI: 10.1209/0295-5075/84/57010

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  • Spin-singlet superconductivity with multiple gaps in PrFeAsO0.89F0.11 Reviewed

    K. Matano, Z. A. Ren, X. L. Dong, L. L. Sun, Z. X. Zhao, Guo-Qing Zheng

    Europhysics Letters   83 ( 5 )   57001-p1 - 57001-p4   2008.7

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    We report As-75 and F-19 NMR studies on the superconducting properties of the newly discovered compound PrFeAsO0.89F0.11 (T-c = 45 K). The Knight shift in the direction of H parallel to ab-plane decreases below T-c to almost zero, which indicates spin-singlet pairing. The temperature dependencies of both the Knight shift and the spin lattice relaxation rate indicate that there are two gaps opening below T-c, with nodes in the gap function. Copyright (c) EPLA, 2008.

    DOI: 10.1209/0295-5075/83/57001

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  • Evidence for d-wave pairing in the cobalt oxide superconductor NaxCoO2 center dot 1.3H(2)O Reviewed

    K. Matano, Guo-Qing Zheng, D. P. Chen, C. T. Lin

    Physica B: Condensed Matter   403   1107 - 1108   2007.11

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We report the spin susceptibility in the superconducting state of the cobalt oxide superconductor NaxCoO2 center dot 1.3H(2)O, via the (CO)-C-59 Knight shift measurements. Along both a- and c-axis directions, the shift decreases below T-c. At T = 1.7 K, the shift along the a-axis, K-a increases with increasing the strength of magnetic field (H), following a root H variation. Together with the T-3 dependence of the spin-lattice relaxation rate, 1/T-1, these results indicate unambiguously that the Cooper pairs are in the spin-singlet form and that there exist nodes in the gap function. The data are most consistent with a d-wave symmetry. (C) 2007 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physb.2007.10.251

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  • Pressure dependence of the superconducting transition and electron correlations in NaxCoO2 center dot 1.3H(2)O Reviewed

    E. Kusano, S. Kawasaki, K. Matano, Guo-Qing Zheng, R. L. Meng, J. Cmaidalka, C. W. Chu

    Physical Review B   76 ( 10 )   100506-1 - 100506-4   2007.9

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    We report T-c and Co-59 nuclear quadrupole resonance measurements on the cobalt oxide superconductor NaxCoO2 center dot 1.3H(2)O (T-c=4.8 K) under hydrostatic pressure (P) up to 2.36 GPa. T-c decreases with increasing pressure at an average rate of -0.49 +/- 0.09 K/GPa. At low pressures P <= 0.49 GPa, the decrease of T-c is accompanied by a weakening of the spin correlations at a finite wave vector and a reduction of the density of states (DOS) at the Fermi level. At high pressures above 1.93 GPa, however, the decrease of T-c is mainly due to a reduction of the DOS. These results indicate that the electronic and magnetic state of Co is primarily responsible for the superconductivity. The spin-lattice relaxation rate 1/T-1 at P=0.49 GPa shows a T-3 variation below T-c down to T similar to 0.12T(c), which provides compelling evidence for the presence of line nodes in the superconducting gap function.

    DOI: 10.1103/PhysRevB.76.100506

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  • NMR and NQR studies of the pairing symmetry in the superconducting state of NaxCoO2 center dot 1.3H(2)O Reviewed

    K. Matano, G.-Q. Zheng, D. P. Chen, C. T. Lin, J. Cmaidalka, R. L. Meng, W. Chu

    Journal of Magnetism and Magnetic Materials   310 ( 2 )   687 - 689   2006.11

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    We report intensive studies on the cobalt oxide superconductors NaxCoO2 center dot 1.3H(2)O via Co-59 NMR and NQR measurements. In the sample with x = 0.26 and T-c = 4.6, we find that the spin-lattice relaxation rate 1/T-1 shows a T-3 variation below T-c and down to very low temperatures, which indicates the presence of line nodes in the superconducting (SC) gap function. We have also studied the spin susceptibility below T-c via the Knight shift measurement. The spin part of the Knight shift decreases below T-c in both the a- and c-directions indicating singlet spin state of the Cooper pairs. Our results strongly suggest that the superconducting state is a d-wave state. (c) 2006 Elsevier B. V. All rights reserved.

    DOI: 10.1016/j.jmmm.2006.10.531

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  • Spin singlet pairing in the superconducting state of NaxCoO2 center dot 1.3H(2)O: Evidence from a Co-59 Knight shift in a single crystal Reviewed

    Guo-qing Zheng, Kazuaki Matano, D. P. Chen, C. T. Lin

    Physical Review B   73 ( 18 )   180503-1 - 180503-4   2006.5

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    We report a Co-59 Knight-shift measurement in a single crystal of the cobalt oxide superconductor NaxCoO2 center dot 1.3H(2)O (T-c=4.25 K). We find that the shift due to the spin susceptibility, K-s, is substantially large and anisotropic, with the spin shift along the a-axis K-a(s) being two times that along the c-axis K-c(s). The shift decreases with decreasing temperature (T) down to T approximate to 100 K, then becomes a constant until superconductivity sets in. Both K-a(s) and K-c(s) decrease below T-c. Our results indicate unambiguously that the electron pairing in the superconducting state is in the spin singlet form.

    DOI: 10.1103/PhysRevB.73.180503

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  • Evolution of the physical properties with Na content in the cobalt oxide superconductors NaxCoO2 center dot 1.3H(2)O Reviewed

    K Matano, GQ Zheng, J Cmaidalka, Y Sun, RL Meng, CW Chu

    Physica B: Condensed Matter   378-380   871 - 872   2006.2

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    We report measurements on the cobalt oxide superconductors NaxCoO2 (.) 1.3H(2)O over a wide Na content range x = 0.25-0.34, using X-ray diffraction, susceptibility and Co-59 nuclear quadrupole resonance (NQR) techniques. We find that T, increases with decreasing x but reaches to a plateau for x <= 0.28, which correlates closely with the NQR frequency that measures the occupancy of the Co 3d-orbitals. (c) 2006 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physb.2006.01.480

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  • Na content dependence of superconductivity and the spin correlations in NaxCoO2 center dot 1 center dot 3H(2)O Reviewed

    Guo-qing Zheng, Kazuaki Matano, R. L. Meng, J. Cmaidalka, C. W. Chu

    Journal of Physics: Condensed Matter   18 ( 5 )   L63 - L70   2006.1

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    We report systematic measurements using the Co-59 nuclear quadrupole resonance (NQR) technique on the cobalt oxide superconductors NaxCoO2.1.3H(2)O over a wide Na content range x = 0.25-0.34. We find that T, increases with decreasing x but reaches a plateau for x <= 0.28. In the sample with x similar to 0.26, the spin-lattice relaxation rate 1/T-1 shows a T-3 variation below T-c and down h, to T similar to T-c/6, which unambiguously indicates the presence of line nodes in the superconducting (SC) gap function. However, for larger or smaller x, 1/T-1 deviates from the T-3 variation below T similar to 2 K even though the T-c (similar to 4.7 K) is similar, which suggests an unusual evolution of the SC state. In the normal state, the spin correlations at a finite wavevector become stronger upon decreasing x, and the density of states at the Fermi level increases with decreasing x, which can be understood in terms of a single-orbital picture suggested on the basis of LDA calculation.

    DOI: 10.1088/0953-8984/18/5/L02

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MISC

  • 28pTA-9 As-NQR study of LaFeAsO_<1-x>F_x

    Kawasaki S., Matano K., Shimada K., Oka T., Ooe Y., Zheng G.-q., Chen G. F., Luo J. L., Wan N. L.

    Meeting abstracts of the Physical Society of Japan   64 ( 1 )   613 - 613   2009.3

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  • 28pTA-8 As-NMR study in iron arsenide superconductor

    Matano K., Tahara K., Kawasaki S., Zheng G.-q., Ren Z. A., Dong X. L., Sun L., Zhao Z. X., Chen G. F., Luo J. L., Wang N. L.

    Meeting abstracts of the Physical Society of Japan   64 ( 1 )   613 - 613   2009.3

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  • 24pYB-2 NMR in superconducting Na_xCoO_2・yH_2O single crystals IV

    Matano K., Zheng G.-q., Chen D.P., Lin C.T.

    Meeting abstracts of the Physical Society of Japan   63 ( 1 )   612 - 612   2008.2

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  • 23pWH-2 NMR in superconducting Na_xCoO_2・_yH_O single crystals III

    Matano K., Zheng G. -q., Chen D. P., Lin C. T.

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   635 - 635   2007.8

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  • 21aPS-93 ^<59>Co NQR study of Na_xCoO_2・1.3H_2O under high pressure (III)

    Kusano E., Matano K., Kawasaki S., Zheng G-q., Cmaidalka J., Meng R.L., Chu C.W.

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   538 - 538   2007.8

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  • 21aWG-3 NMR in superconducting Na_xCoO_2・yH_2O single crystal s (II)

    Matano K., Zheng G.-q., Chen D. P., Lin C. T.

    Meeting abstracts of the Physical Society of Japan   62 ( 1 )   640 - 640   2007.2

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  • 25pZL-8 d-wave superconductivity in Na_xCoO_2・yH_2O : evidence from Knight Shift in a single crystal

    Matano K., Zheng G.-q., Chen D.P., Lin C.T.

    Meeting abstracts of the Physical Society of Japan   61 ( 2 )   504 - 504   2006.8

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  • 30aUF-1 Na-content Dependence of Superconductivity and Antiferromagnetic fluctuations in Na_xCoO_2*yH_2O

    Matano K., Zheng G.-q., Cmaidalka J., Meng R.L., Chu G.W.

    Meeting abstracts of the Physical Society of Japan   61 ( 1 )   649 - 649   2006.3

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Presentations

  • NMR studies of topological superconductors Invited International conference

    K. Matano

    Materials Research Meeting 2019(MRM2019)  2019.12.13 

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    Event date: 2019.12.10 - 2019.12.14

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Yokohama Symposia, Yokohama  

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  • NMR studies of topological superconductors Invited International conference

    K. Matano

    The 5th Conference on Condensed Matter Physics (CCMP2019)  2019.6.29 

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    Event date: 2019.6.27 - 2019.6.30

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Liyang  

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  • NMRから見たトポロジカル物質 Invited

    俣野和明

    2017年度 日本物理学会秋季大会  2017.9.22 

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    Event date: 2017.9.21 - 2017.9.24

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:岩手大学(上田キャンパス)  

    22pC10-4
    領域4,領域6,領域8合同シンポジウム「超伝導物質および超流動ヘリウム研究の切り開くトポロジカル物理の最前線」

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  • トポロジカル超伝導体のNMR Invited

    俣野和明

    2016年度 応用物理・物理系学会 中国四国支部 合同学術講演会  2016.7.31 

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    Event date: 2016.7.31

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:岡山大学 津島キャンパス  

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  • スピン軌道相互作⽤が強い電⼦系の超伝導 Invited

    俣野和明

    Workshop: CROSSroads of Users and J-PARC 第17回「強相関電子系の凝縮状態」  2016.1.19 

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    Event date: 2016.1.18 - 2016.1.19

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:いばらき量子ビーム研究センター  

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  • 空間反転対称性の破れた超伝導体のNMR/NQR Invited

    俣野和明

    新学術領域研究「対称性の破れた凝縮系におけるトポロジカル量子現象」第2回領域研究会  2011.12.18 

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    Event date: 2011.12.17 - 2011.12.19

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:岡山大学創立五十周年記念館  

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  • NMR/NQR studies of non-centrosymmetric superconductors Invited International conference

    International Workshop for Young Researchers on Topological Quantum Phenomena in Condensed Matter with Broken Symmetries  2011.11.3 

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    Event date: 2011.11.1 - 2011.11.5

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Laforet Biwako, Shiga Prefecture  

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  • トポロジカル超伝導体CuxBi2Se3の作製と物性測定 II International coauthorship

    横山武蔵, 西垣颯, 俣野和明, 神戸高志, 鄭国慶

    日本物理学会第76回年次大会(2021年)  2021.3.15 

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    Event date: 2021.3.12 - 2021.3.15

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:オンライン開催  

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  • 重い電子系反強磁性超伝導体CeRh0.5Ir0.5In5における局在・遍歴転移とギャップレス超伝導 International coauthorship

    川崎慎司, 岡利英, 反り目章, 小亀雄司, 上本和宏, 俣野和明, J. Guo, S. Cai, Liling Sun, J. L. Sarrao, J. D. Thompson, 鄭国慶

    日本物理学会第76回年次大会(2021年)  2021.3.14 

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    Event date: 2021.3.12 - 2021.3.15

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:オンライン開催  

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  • Transition of the gap symmetry in topological superconductors CuxBi2Se3 International coauthorship International conference

    K. Matano, T. Kawai, C. G. Wang, Y. Kandori, Y. Honoki, T. Kambe, Guo-qing Zheng

    International Conference on Topological Materials Science 2019 (TopoMat2019)  2019.12.5 

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    Event date: 2019.12.3 - 2019.12.7

    Language:English   Presentation type:Poster presentation  

    Venue:Kyoto University  

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  • Unconventional Gapless Superconductivity at the Quantum Critical Point in CeRh0.5Ir0.5In5 International conference

    S. Kawasaki, T. Oka, A. Sorime, Y. Kogame, K. Uemoto, K. Matano, J. Guo, S. Cai, L. L. Sun, J. L. Sarrao, J. D. Thompson, and Guo-qing Zheng

    International conference on strongly correlated electron systems 2019 (SCES2019)  2019.9.25 

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    Event date: 2019.9.23 - 2019.9.28

    Language:English  

    Venue:Okayama Convention Center, Okayama  

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  • NMR studies of chiral noncentrosymmetric superconductor TaRh2B2 International coauthorship International conference

    Ryo Ogura, Mateo Fountaine, Kazuaki Matano, Shinji Kawasaki, Guo-qing Zheng

    International conference on strongly correlated electron systems 2019 (SCES2019)  2019.9.24 

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    Event date: 2019.9.23 - 2019.9.28

    Language:English   Presentation type:Poster presentation  

    Venue:Okayama Convention Center, Okayama  

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  • CuxBi2Se3超伝導体の作製と物性測定II International coauthorship

    神鳥吉史, 河合哲大, 厚朴優樹, 俣野和明, 神戸高志, 鄭国慶

    日本物理学会 2019年秋季大会  2019.9.13 

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    Event date: 2019.9.10 - 2019.9.13

    Language:Japanese  

    Venue:岐阜大学  

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  • キラル結晶構造を持つ空間反転対称性の破れた超伝導体(Ta,Nb)Rh2B2のNMR測定

    小椋亮, FOUNTAINE Mateo, 俣野和明, 川崎慎司, 鄭国慶

    日本物理学会 2019年秋季大会  2019.9.12 

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    Event date: 2019.9.10 - 2019.9.13

    Language:Japanese  

    Venue:岐阜大学  

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  • 円偏光二次元光電子回折法によるトポロジカル超伝導体CuドープBi<sub>2</sub>Se<sub>3</sub>のドーパントサイトの観察

    荻昌史, 橋本由介, 桃野浩樹, 深見駿, 小林進大, 彭大巍, 俣野和明, 松田博之, 田口宗孝, 鄭国慶, 大門寛

    2018年日本表面真空学会学術講演会  2018.11.20 

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    Event date: 2018.11.19 - 2018.11.21

    Language:Japanese   Presentation type:Poster presentation  

    Venue:神戸国際会議場  

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  • CuxBi2Se3超伝導体の作製と物性測定

    河合哲大, 厚朴優樹, 神鳥吉史, 俣野和明, 神戸高志, 鄭国慶

    日本物理学会 第73回年次大会(2018年)  2018.3.25 

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    Event date: 2018.3.22 - 2018.3.25

    Presentation type:Oral presentation (general)  

    Venue:東京理科大学(野田キャンパス)  

    25aB101-7

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  • 空間反転対称性の破れた超伝導体のNMR/NQR

    八谷 諒, 森 洋貴, 前田 賢輝, 俣野 和明, 鄭 国慶

    日本物理学会 第 71 回年次大会  2016.3.19 

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    Event date: 2016.3.19 - 2016.3.22

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東北学院大学 泉キャンパス  

    19aBN-9

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  • 超伝導体LaPt<sub>2-x</sub>Ge<sub>2+x</sub>の構造相転移に関するNMR/NQR法を用いた研究

    前田賢輝, 俣野和明, 八谷諒, 小口多美夫, 鄭国慶

    日本物理学会第 70 回年次大会(2015 年)  2015.3.22 

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    Event date: 2015.3.21 - 2015.3.24

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:早稲田大学 早稲田キャンパス  

    22pBC-10

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  • Superconductivity in logally-noncentrosymmetric SrPtAs International conference

    Ushimado International Workshop on Physics and Chemistry of Novel Superconductors and Related Materials  2014.11.9 

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    Event date: 2014.11.8 - 2014.11.10

    Language:English   Presentation type:Poster presentation  

    Venue:Hotel ‘Limani’, Ushimado  

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  • NMR/NQR study of the structual phase transition in the superconductors LaPt<sub>2-x</sub>Ge<sub>2+x</sub> International conference

    S. Maeda, K. Matano, R. Yatagai, Guo-qing Zheng

    Ushimado International Workshop on Physics and Chemistry of Novel Superconductors and Related Materials  2014.11.9 

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    Event date: 2014.11.8 - 2014.11.10

    Language:English   Presentation type:Poster presentation  

    Venue:Hotel ‘Limani’, Ushimado  

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  • 空間反転対称性の欠如したパリティ混合超伝導体Li<sub>2</sub>T<sub>3</sub>B(T:Pd,Pt)の非磁性不純物効果の異常性

    包桂芝, 江口学, 小野晶子, 俣野和明, 稲田佳彦, 前野悦輝, 市岡優典, 鄭国慶

    日本物理学会 第69回年次大会(2014)  2014.3.30 

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    Event date: 2014.3.27 - 2014.3.30

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東海大学 湘南キャンパス  

    30aCM-10

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  • LaPt<sub>2-x</sub>Ge<sub>2+x</sub>の超伝導と電子相図

    前田賢輝, 俣野和明, 澤岡浩貴, 稲田佳彦, 鄭国慶

    日本物理学会 第69回年次大会(2014)  2014.3.30 

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    Event date: 2014.3.27 - 2014.3.30

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東海大学 湘南キャンパス  

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  • トポロジカル結晶超伝導体Sn<SUB>1-x</SUB>In<SUB>x</SUB>TeのNMR法による研究

    勝部翔太, 俣野和明, MNovak, 瀬川耕司, 安藤陽一, 鄭国慶

    日本物理学会 第69回年次大会(2014)  2014.3.28 

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    Event date: 2014.3.27 - 2014.3.30

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東海大学 湘南キャンパス  

    28aBF-11

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  • トポロジカル超伝導体候補物質Cu<SUB>x</SUB>Bi<SUB>2</SUB>Se<SUB>3</SUB>のNMR法による研究

    俣野和明, 山本裕之, 上島啓司, 岩瀬文達, M.Kriener, 瀬川耕司, 安藤陽一, 鄭国慶

    日本物理学会 第69回年次大会(2014)  2014.3.28 

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    Event date: 2014.3.27 - 2014.3.30

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東海大学 湘南キャンパス  

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  • NMR/NQR studies on non-centrosymmetric and locally non-centrosymmetric superconductors International conference

    International Workshop for Young Researchers on Topological Quantum Phenomena in Condensed Matter with Broken Symmetries 2013  2013.10.24 

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    Event date: 2013.10.22 - 2013.10.26

    Language:English   Presentation type:Poster presentation  

    Venue:Culture Resort Festone  

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  • LaPt<sub>2-x</sub>Ge<sub>2+x</sub>の結晶構造と超伝導

    前田賢輝, 俣野和明, 澤岡浩貴, 稲田佳彦, 鄭国慶

    日本物理学会2013年秋期大会  2013.9.27 

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    Event date: 2013.9.25 - 2013.9.29

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:徳島大学 常三島キャンパス  

    27pEB-8

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  • 空間反転対称性の破れた超伝導体Li<sub>2</sub>(Pd,Pt)<sub>3</sub>Bの不純物効果およびSrPtAsのNMR/NQRによる研究

    有馬和宏, 原田翔太, 西窪義博, 工藤一貴, 野原実, 包桂芝, 稲田佳彦, 俣野和明, 鄭国慶

    日本物理学会2012年秋期大会  2012.9.19 

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    Event date: 2012.9.18 - 2012.9.22

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:横浜国立大学 常盤台キャンパス  

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  • 空間反転対称性の破れた超伝導体LaBiPtとBiPdのNMR/NQR

    俣野和明, 室裕司, 高畠敏郎, Bhanu Joshi, S. Ramakrishnan, 鄭国慶

    日本物理学会第2012年秋季大会  2012.9.19 

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    Event date: 2012.9.18 - 2012.9.22

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:横浜国立大学 常盤台キャンパス  

    19aGB-4

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  • NMR/NQR Studies of Non-centrosymmetric Superconductors

    2012.5.19 

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    Event date: 2012.5.16 - 2012.5.20

    Language:English   Presentation type:Poster presentation  

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  • NMR/NQR Studies of the Non-centrosymmetric Superconductor LaPtBi & BiPd International conference

    K. Matano, Y. Muro, T. Takabatake, Bhanu Joshi, S. Ramakrishnan, Guo-qing Zheng

    International conference on topological quantum phenomena  2012.5.17 

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    Event date: 2012.5.16 - 2012.5.20

    Language:English   Presentation type:Poster presentation  

    Venue:Nagoya University, Nagoya  

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  • 空間反転対称性の破れた超伝導体のNMR/NQR

    俣野和明, 室裕司, 高畠敏郎, Bhanu Joshi, S. Ramakrishnan, 鄭国慶

    日本物理学会第67回年次大会  2012.3.25 

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    Event date: 2012.3.24 - 2012.3.27

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:関西学院大学 西宮上ケ原キャンパス  

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  • 空間反転対称性の破れた超伝導体LaPtBiのNMR/NQR

    俣野和明, 鄭国慶, 室裕司, 高畠敏郎

    日本物理学会2011年秋季大会  2011.9.24 

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    Event date: 2011.9.21 - 2011.9.24

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:富山大学  

    24aGE-5

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  • 空間反転対称性の破れた超伝導体LaPtBiのNQR

    俣野和明, 室裕司, 高畠敏郎, 鄭国慶

    日本物理学会第66回年次大会  2011.3.25 

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    Event date: 2011.3.25 - 2011.3.28

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:新潟大学五十嵐キャンパス  

    25pED-2

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  • 空間反転対称性の破れた超伝導体LaPtBiのNQR

    俣野和明, 室裕司, 高畠敏郎, 鄭国慶

    新学術領域研究「対称性の破れた凝縮系におけるトポロジカル量子現象」第1回領域研究会  2010.12.18 

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    Event date: 2010.12.18 - 2010.12.20

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都大学 百周年時計台記念館  

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  • 鉄ヒ素系超伝導体のAs-NQRによる研究 International coauthorship

    川崎慎司, 俣野和明, 島田健史, 岡利英, 大江陽介, 鄭国慶, G. F. Chen, J. L. Luo, N. L. Wan

    日本物理学会 第64回年次大会(2009)  2009.3.28 

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    Event date: 2009.3.27 - 2009.3.30

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:立教大学、立教池袋中学・高校  

    28pTA-9

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  • 鉄ヒ素系超伝導体のAs-NMRによる研究 International coauthorship

    俣野和明, 田原圭介, 川崎慎司, 鄭国慶, Z. A. Ren, X. L. Dong, L. Sun, Z. X. Zhao, 島田健史, G. F. Chen, J. L. Luo, N. L. Wang

    日本物理学会2009年春季大会  2009.3.28 

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    Event date: 2009.3.27 - 2009.3.30

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:立教大学、立教池袋中学・高校  

    28pTA-8

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  • BREO<sub>1-x</sub>F<sub>x</sub>FeAsのNMRによる研究 International coauthorship

    島田健史, 俣野和明, 田原圭介, 川崎慎司, 鄭国慶, Z. A. Ren, X. L. Dong, L. Sun, Z. X. Zhao

    2008.9.22 

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    Event date: 2008.9.20 - 2008.9.23

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手大学 上田キャンパス  

    22pYA-13

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  • LaNiAsO<sub>1-x</sub>F<sub>x</sub>のNMRによる研究

    田渕貴久, 俣野和明, 川崎慎司, 鄭国慶, Z. Li, G. F. Chen, J. L. Luo, N. L. Wang

    日本物理学会2008年秋期大会  2008.9.22 

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    Event date: 2008.9.20 - 2008.9.23

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手大学 上田キャンパス  

    22pYA-12

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  • 単結晶Na<sub>x</sub>CoO<sub>2</sub>・yH<sub>2</sub>OにおけるNMR測定 V International coauthorship

    俣野和明, 鄭国慶, D. P. Chen, C. T. Lin

    日本物理学会2008年秋期大会  2008.9.21 

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    Event date: 2008.9.20 - 2008.9.23

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手大学 上田キャンパス  

    21aQE-1

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  • 単結晶Na<sub>x</sub>CoO<sub>2</sub>・yH<sub>2</sub>OにおけるNMR測定 IV International coauthorship

    俣野和明, 鄭国慶, D. P. Chen, C. T. Lin

    日本物理学会 第63回年次大会  2008.3.24 

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    Event date: 2008.3.22 - 2008.3.26

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:近畿大学 本部キャンパス  

    24pYB-2

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  • 単結晶Na<sub>x</sub>CoO<sub>2</sub>・yH<sub>2</sub>OにおけるNMR測定(III) International coauthorship

    俣野和明, 鄭国慶, D. P. Chen, C. T. Lin

    日本物理学会 第62回年次大会  2007.9.23 

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    Event date: 2007.9.21 - 2007.9.24

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:北海道大学 札幌キャンパス  

    23pWH-2

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  • Na_xCoO_2・1.3H_2Oの高圧下^<59>Co-NQRによる研究(III) International coauthorship

    草野江理, 俣野和明, 川崎慎司, 鄭国慶, J. Cmaidalka, R. L. Meng, C. W. Chu

    日本物理学会 第62回年次大会  2007.9.21 

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    Event date: 2007.9.21 - 2007.9.24

    Language:Japanese   Presentation type:Poster presentation  

    Venue:北海道大学 札幌キャンパス  

    21aPS-93

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  • 単結晶Na<sub>x</sub>CoO<sub>2</sub>・yH<sub>2</sub>OにおけるNMR測定(II) International coauthorship

    俣野和明, 鄭国慶, D. P. Chen, C. T. Lin

    日本物理学会2007年春期大会  2007.3.21 

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    Event date: 2007.3.18 - 2007.3.21

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:鹿児島大学 郡元キャンパス  

    21aWG-3

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  • Na<sub>x</sub>CoO<sub>2</sub>・yH<sub>2</sub>Oにおけるd波超伝導 : 単結晶ナイトシフト測定 International coauthorship

    俣野和明, 鄭国慶, D. P. Chen, C. T. Lin

    日本物理学会2006年秋期大会  2006.9.25 

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    Event date: 2006.9.23 - 2006.9.26

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:千葉大学 西千葉キャンパス  

    25pZL-8

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  • Na<sub>x</sub>CoO<sub>2</sub>・yH<sub>2</sub>Oにおける超伝導と反強磁性スピンゆらぎのNa濃度依存性(NQR/NMR) International coauthorship

    俣野和明, 鄭国慶, R. L. Meng, J. Cmaidalka, C. W. Chu

    日本物理学会2005年秋期大会  2005.9.21 

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    Event date: 2005.9.19 - 2005.9.22

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:同志社大学 京田辺キャンパス  

    21aXD-8

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  • Na<sub>x</sub>CoO<sub>2</sub>・yH<sub>2</sub>O (y=0, 1.3) の NQR による研究

    俣野和明, 鄭国慶, R. L. Meng, J. Cmaidalka, C. W. Chu

    日本物理学会2004年秋期大会  2004.9.13 

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    Event date: 2004.9.12 - 2004.9.15

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:青森大学  

    13aRC-8

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Awards

  • 金光奨励賞

    2021.10   岡山大学  

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  • 仁科賞

    2009.3   岡山県  

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    Country:Japan

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Research Projects

  • トポロジカル超伝導体CuxBi2Se3の物性解明

    Grant number:20K03862  2020.04 - 2023.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    俣野 和明

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    Grant amount:\4290000 ( Direct expense: \3300000 、 Indirect expense:\990000 )

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  • Physics of Spin-triplet superconductivity

    Grant number:19H00657  2019.04 - 2023.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)  Grant-in-Aid for Scientific Research (A)

    鄭 国慶, 俣野 和明, 川崎 慎司, 市岡 優典

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    Grant amount:\44590000 ( Direct expense: \34300000 、 Indirect expense:\10290000 )

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  • NMR sturies of Topological Superconductors

    Grant number:17K14340  2017.04 - 2019.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)  Grant-in-Aid for Young Scientists (B)

    俣野 和明

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    Grant amount:\4160000 ( Direct expense: \3200000 、 Indirect expense:\960000 )

    質量を持たないディラック電子の存在などで注目されているトポロジカル絶縁体研究は理論・実験共に着実に進んでいる。一方で、トポロジカル超伝導体は特異な性質や量子コンピューターなどへの応用が期待されており、複数の候補が上がっているがまだ進んでいない。本研究では、複数の候補物質について試料作製及びNMR測定を行い、トポロジカル超伝導体の理解を深めることを目的とする。
    今年度は最近発見されたトポロジカル超伝導体候補物質CuxBi2Se3単結晶試料の作製及び物性評価、InxSn1-xTe、PbTaSe2の超伝導対称性研究を行った。
    超伝導状態になると、結晶の3回対称とは異なる2回対称が超伝導物性に現れ、スピン三重項超伝導であるCuxBi2Se3では、2回対称が現れる方向が論文によって異なることが問題になっていた。今回新たに複数の試料を作成し物性測定を行った結果、2回対称が現れる方向が試料によって異なることを発見し本質的なものであると裏付けた、本研究結果は日本物理学会第73回年次大会で報告した。この結果については現在論文を投稿中である。
    トポロジカル結晶絶縁体SnTeにInをドープすることで超伝導が発現するInxSn1-xTeはトポロジカル超伝導体の候補として注目を集めていたが、超伝導対称性を決定するためにNMR測定を行った結果、通常のフルギャップシングレット超伝導体であるというこを発見しPhysical Review B紙に論文として報告した。
    同様にトポロジカル超伝導候補物質であるPbTaSe2の超伝導対称性をNMR法を用いて研究し、超伝導対称性を明らかにした。この結果もPhysical Review B紙に論文として報告した。
    また、日本物理学会2017年秋季大会にて本研究に関するシンポジウム招待講演を行った。さらに、物理学科誌2018年2月号にて、本研究に関する解説を発表した。

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  • NMR study on novel superconductivity in materials with special structures

    Grant number:16H04016  2016.04 - 2019.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    鄭 国慶, 俣野 和明, 川崎 慎司

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    Grant amount:\17810000 ( Direct expense: \13700000 、 Indirect expense:\4110000 )

    本研究の目的は三角格子や六角晶など特殊な結晶構造を有する物質において、新奇な超伝導状態を核磁気共鳴(NMR)法によって探索することである。研究対象物質の中に、空間反転対称性が破れるものもあり、反対称スピン軌道相互作用が強く、スピン三重項超伝導が期待できる。また、バンド構造にバン・ホッフ特異点があり、非従来型超伝導状態の実現に有利な条件が整っている物質もある。本研究では、NMR等の測定を行い、スピン格子緩和率やナイトシフトの温度・結晶軸方向及び磁場依存性から、特殊な結晶構造が生み出す新奇超伝導の物性を明らかにする。
    六方晶の層状物質で空間反転対称性が破れたPbTaSe2について調べた。この物質は、デイラック型のバンドを持ち、ワイル型半金属であるが、4.05Kで超伝導に転移する。NMR測定した結果、超伝導ギャップが等方的に開くこと、電子対のスピンが一重項状態にあることを明らかにした。しかし、超伝導転移温度直下に通常現れるコヒーレンスピークが見られず、デイラック電子の影響が表れている可能性があることを見出した。
    擬スクッテルダイト超伝導体(Sr1-xCax)3Ir4Sn13やCa3Rh4Sn13において、構造相転移温度よりも高温で電子状態に前駆的な異常を示すことや、反強磁性的な電子相関があることを明らかにした。
    鉄系高温超伝導体LaFeAsO1-xFxにおいて、x=0.03では反強磁性と超伝導が微視的に共存すること、x>0.5における構造相転移が低ドープ(x<0.3)側に見られるものと同じであることを明らかにした。また、x>0.5では電子相関が弱いにもかかわらず超伝導転移温度が高いのは、ネマチックゆらぎに因る可能性が高いことを指摘した。

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  • Novel phenomena in electronic fluids with broken inversion symmetry

    Grant number:22103004  2010.04 - 2015.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)  Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    ZHENG Guo-qing, UENO Kazunori, SEGAWA Kouji, NOJIMA Tsutomu, INADA Yoshihiko, SHISHIDOU Tatsuya, ANDO Yoichi, NAGAOSA Naoto, IWASA Yoshihiro, HANAGURI Tetsuo, OSADA Toshihito, MATANO Kazuaki, YOKOYA Takayoshi

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    Grant amount:\246870000 ( Direct expense: \189900000 、 Indirect expense:\56970000 )

    In the electronic fluids with broken inversion symmetry and strong spin-orbit coupling, we have investigated various topological quantum phenomena and obtained the following results. In noncentrosymmetric superconductors, we clarified the conditions necessary for bringing about a large spin-triplet component. We have succeeded in synthesizing new topological insulators and found that CuxBi2Se3 is a spin-triplet superconductor. We discovered electric-field-effect induced superconductivity in KTaO3 which cannot be made superconducting by conventional chemical doping method.

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  • コバルト酸化物超伝導体のNQR/NMRによる研究

    Grant number:07J02735  2007 - 2009

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows  Grant-in-Aid for JSPS Fellows

    俣野 和明

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    Grant amount:\1800000 ( Direct expense: \1800000 )

    我々のこれまでのスピン格子緩和率や超伝導状態におけるナイトシフト測定のにより、コバルト酸化物超伝導体は、銅酸化物高温超伝導体と同じくd波超伝導と一致するという成果が得られていたが、今年度はさらにコバルト酸化物超伝導体がd波超伝導であることを示すために、超伝導状態におけるナイトシフトの磁場・温度依存性を測定した。測定の結果、超伝導状態におけるナイトシフトが磁場の平方根に比例することがわかった、これは超伝導ギャップ関数にラインノードがあることを示す結果であり、d波超伝導に一致するな結果である。さらに、ナイトシフトの磁場・温度依存性がd波超伝導モデルとよく一致することを確認し、d波超伝導モデルでのフィッティングにより、磁場誘起による残留状態密度も確認することができた。これらのことからd波超伝導である証拠をさらに得ることが出来たことは重要な結果である。
    また、様々な良質の単結晶試料を用い物理量の測定を行った結果、ナイトシフト、1/T1T共にナトリウム濃度に依存し、ナトリウムドープによって状態密度が変化しているという結果を得ることができた。これまでの我々の研究により、コバルト酸化物超伝導では銅酸化物高温超伝導体と同じく超伝導転移温度と状態密度、スピン相関の大きさとの相関が指摘されており、ナトリウムドープによって状態密度が変化しているという結果は非常に重要である。
    2008年の2月に発見された鉄ヒ素系超伝導体はコバルトや銅酸化物と似ており超伝導転移温度も高く、注目を集めている物質である。それらの物質に関しても測定を行い、超伝導の対象性について研究した。その結果、超伝導ギャップが2つあるということを突き止めた。

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  • Information Physics Experiments 2 (2021academic year) 3rd and 4th semester  - 月5,月6,月7,月8

  • Information Physics Experiments 2 (2021academic year) 3rd and 4th semester  - 月5,月6,月7,月8

  • Physics Experiments 2 (2021academic year) 3rd and 4th semester  - [第3学期]月5,月6,月7,月8, [第4学期]月4,月5,月7,月8

  • Superconductivity (2021academic year) Late  - 水5,水6

  • Information Physics Experiments 2 (2020academic year) 3rd and 4th semester  - 月3,月4,月5,月6

  • Information Physics Experiments 2 (2020academic year) 3rd and 4th semester  - 月3,月4,月5,月6

  • Physics Experiments 2 (2020academic year) 3rd and 4th semester  - 月3,月4,月5,月6

  • Superconductivity (2020academic year) Late  - 水4,水5

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