二次元量子スピン液体の熱輸送現象(最近の研究から)  [in Japanese] Thermal Transport Studies of Quantum Spin Liquids(Current Topics)  [in Japanese]

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Abstract

磁性体の持つスピンの長距離秩序が量子力学的揺らぎにより融解した量子スピン液体状態は,長年にわたって論争の続く未知の状態である.最近,幾何学的フラストレーションを持つ二次元三角格子上に反強磁性的相互作用をするスピンが配列した二種類の有機化合物において,量子スピン液体状態の候補物質が発見された.我々は極低温における熱伝導率測定により,これらの系におけるスピン液体状態を調べた結果,ギャップを持たない連続的な励起を持つスピン液体状態が存在することを見出した.特に準粒子がほとんど散乱を受けずに熱を運ぶことや,磁場によって誘起される磁気的でギャップを持った準粒子も共存することなど,スピン液体の興味ある性質の一端が明らかになってきた.

Quantum spin liquids (QSLs) are fluid-like states of spins realized by destroying its long-range ordered state by quantum fluctuation. In two-dimensional system, QSL may be realized under geometrical frustration. The ground state of QSL and its exotic phenomena, such as fractionalized excitation with an artificial gauge field, have been extensively discussed for decades, yet to be identified. We employ thermal transport measurements on newly discovered QSL candidates, κ-(BEDT-TTF)_2Cu_2(CN)_3 and EtMe_3Sb[Pd(dmit)_2]_2, and report that the two organic insulators possess different QSLs characterized by different elementary excitations. In κ-(BEDT-TTF)_2Cu_2(CN)_3, heat transport is thermally activated in low temperatures, suggesting presence of a spin gap in this QSL. In stark contrast, in EtMe_3Sb[Pd(dmit)_2]_2, a sizable temperature-linear term of thermal conductivity is clearly resolved in the zero-temperature limit, showing gapless excitation with long mean free path (〜1,000 lattice distances). The latter demonstrates a novel feature of QSL as a quantum condensed state with long-distance coherence.

Journal

  • Butsuri

    Butsuri 66(12), 928-932, 2011

    The Physical Society of Japan

References:  39

  • <no title>

    BALENTS L.

    Nature 464, 199, 2010

    Cited by (1)

  • <no title>

    ANDERSON P. W.

    Mater. Rev. Bull. 8, 153, 1973

    Cited by (1)

  • <no title>

    ANDERSON P. W.

    Science 225, 1196, 1987

    Cited by (1)

  • <no title>

    LEE P. A.

    Science 321, 1306, 2008

    Cited by (1)

  • <no title>

    SACHDEV S.

    Nature Phys. 4, 173, 2008

    Cited by (1)

  • <no title>

    SHIMIZU Y.

    Phys. Rev. Lett. 91, 107001, 2003

    Cited by (1)

  • <no title>

    ITOU T.

    Nature Phys. 6, 673, 2010

    Cited by (1)

  • <no title>

    HIROI Z.

    J. Phys. Soc. Jpn. 70, 3377, 2001

    Cited by (1)

  • <no title>

    SHORES M. P.

    J. Am. Chem. Soc. 127, 13462, 2005

    Cited by (1)

  • <no title>

    OKAMOTO Y.

    J. Phys. Soc. Jpn. 78, 033701, 2009

    Cited by (1)

  • <no title>

    YAMASHITA M.

    Nature Phys. 5, 44, 2009

    Cited by (1)

  • <no title>

    YAMASHITA M.

    Science 328, 1246, 2010

    Cited by (1)

  • <no title>

    SINGH R. R. P.

    Phys. Rev. B 76, 180407(R), 2007

    Cited by (1)

  • <no title>

    SINGH R. R. P.

    Phys. Rev. B 77, 144415, 2008

    Cited by (1)

  • <no title>

    YAN S.

    Science

    Cited by (1)

  • <no title>

    清水康弘

    固体物理 39, 545, 2004

    Cited by (1)

  • <no title>

    ITOU T.

    Phys. Rev. B 77, 104413, 2008

    Cited by (1)

  • <no title>

    Phys. Rev. B 60, 1064, 1999

    Cited by (1)

  • <no title>

    MORITA H.

    J. Phys. Soc. Jpn. 71, 2109, 2002

    Cited by (1)

  • <no title>

    YOSHIOKA T.

    Phys. Rev. Lett. 103, 036401, 2009

    Cited by (1)

  • <no title>

    TAMURA M.

    Polyhedron 24, 2817, 2005

    Cited by (1)

  • <no title>

    YAMASHITA S.

    Nature Commun. 2, 275, 2011

    Cited by (1)

  • <no title>

    堺和光

    日本物理学会誌 58, 422, 2003

    Cited by (1)

  • <no title>

    PRATT F. L.

    Nature 471, 612, 2011

    Cited by (1)

  • <no title>

    YAMASHITA S.

    Nature Phys. 4, 459, 2008

    Cited by (1)

  • <no title>

    SHIMIZU Y.

    Phys. Rev. B 73, 140407(R), 2006

    Cited by (1)

  • <no title>

    JOHNSTON D. C.

    Phys. Rev. B 74, 184430, 2006

    Cited by (1)

  • <no title>

    LEE S.-S.

    Phys. Rev. Lett. 95, 036403, 2005

    Cited by (1)

  • <no title>

    KATSURA H.

    Phys. Rev. Lett. 104, 066403, 2010

    Cited by (1)

  • <no title>

    QI Y.

    Phys. Rev. Lett. 102, 176401, 2009

    Cited by (1)

  • <no title>

    MERMIN N. D.

    Phys. Rev. Lett. 17, 1133, 1966

    DOI  Cited by (2)

  • <no title>

    MASUTOMI R.

    Phys. Rev. Lett. 92, 025301, 2004

    Cited by (8)

  • <no title>

    BRAMWELL S. T.

    Science 294, 1495, 2001

    Cited by (9)

  • <no title>

    BERNU B.

    Phys. Rev. Lett. 69, 2590, 1992

    Cited by (3)

  • <no title>

    CAPRIOTTI L.

    Phys. Rev. Lett. 82, 3899, 1999

    Cited by (8)

  • <no title>

    MISGUICH G.

    Phys. Rev. Lett. 81, 1098, 1998

    Cited by (7)

  • <no title>

    LIMING W.

    Phys. Rev. B 62, 6372, 2000

    Cited by (2)

  • <no title>

    SOLOGUBENKO A. V.

    Phys. Rev. B 64, 054412, 2001

    Cited by (14)

  • <no title>

    MOTRUNICH O. I.

    Phys. Rev. B 72, 045105, 2005

    DOI  Cited by (4)

Codes

  • NII Article ID (NAID)
    110008799179
  • NII NACSIS-CAT ID (NCID)
    AN00196952
  • Text Lang
    JPN
  • Article Type
    REV
  • ISSN
    0029-0181
  • NDL Article ID
    023379870
  • NDL Call No.
    Z15-13
  • Data Source
    CJP  NDL  NII-ELS  J-STAGE 
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