2001 Fiscal Year Annual Research Report

電子スピン共鳴によるスピンギャップ直接観測の理論的研究

Research Project

Project/Area Number	13640371
Research Institution	Tokyo Metropolitan Institute of Technology
Principal Investigator	坂井徹東京都立科学技術大学, 工学部, 助教授 (60235116)
Keywords	スピンギャップ / 電子スピン共鳴 / 強磁場 / スピンラダー / 強相関電子系 / 高温超伝導
Research Abstract	今年度の研究実績を、(1)スピンギャップ系の一般的性質、及び(2)スピンギャップ系の電子スピン共鳴で観測される性質に分けて記す。 (1)スピンギャップ系の一般的性質スピン・パイエルス系、スピン・ラダー系、直交ダイマー系等のスピンギャップ系において強磁場によって誘起されるいくつかの新しい現象を理論的に提唱し、これまでに観測されている実験事実との比較を行った。主な現象としては、磁場誘起長距離秩序、磁場誘起スピンギャップによる磁化曲線のプラトー、異常なスピンフロップ転移等があげられる。このうち、磁場誘起秩序は、NDMAP、NDMAZと呼ばれる擬一次元スピン1反強磁性化合物で観測されており、本研究による予測と実験結果はよく一致している。また最近、BIP-TENOと呼ばれる有機化合物のスピン1スピンラダー系が合成され、その強磁場磁化測定の結果、磁化曲線のプラトーが観測されたことを受け、このプラトーの起源が長距離の反強磁性交換相互作用によるフラストレーションであることを理論的に解明した。また強相関電子系、とくに高温超伝導体で観測されている擬スピンギャップの問題の起源が反強磁性相関であることを示した。 (2)スピンギャップ系め電子スピン共鳴で観測される性質スピンギャップに相当する電子スピン共鳴の直接遷移は、スピンの保存則から禁止されており、本来観測されないことが知られているが、いくつかのスピンギャップ系ではこの遷移が観測されている。とくにスピン・パイエルス系として知られるCuGeO_3について、この直接遷移の起源が交代磁場の効果である可能性を、有限クラスターの数値対角化の解析により示した。

Research Products

(23 results)

All Other

All Publications (23 results)

[Publications] Toru Sakai: "Stripes due to the next-nearest neighbor exchange in high-Tc cuprates"Physical Review B. 63. 140509(R)-1-140509(R)-3 (2001)
[Publications] Toru Sakai: "Pseudogap Induced by Antiferromagnetic Spin Correlation in High-Temperature Superconductors"Journal of Physical Society of Japan. 70. 272-277 (2001)
[Publications] Toru Sakai: "Pseudo Gap and Antiferrornagnetic Spin Correlation in High-Tc Cuprates"Journal of Physics and Chemistry of Solids. 62. 203-206 (2001)
[Publications] Masayuki Hagiwara: "High Field Magnetization of an S=1/2 Zigzag Chain Compound (N_2H_5)CuCl_3"Physica B. 294-295. 83-86 (2001)
[Publications] Toru Sakai: "Selection Rule of ESR for Spin Gap Systems"Physica B. 294-295. 26-29 (2001)
[Publications] Toru Sakai: "Local Lattice distortion in High-Tc Cuprates"Journal of Synchrotron Radiation. 8. 848-850 (2001)
[Publications] Kiyomi Okamoto: "Magnetization Plateau of an S=1 Spin Ladder"Journal of Physical Society of Japan. 70. 636-639 (2001)
[Publications] Toru Sakai: "Quantum Magnetization Plateaux in Ferrimagnetic Spin Chains"Journal of Magnetism and Magnetic Materials. 226-230. 645-646 (2001)
[Publications] Toru Sakai: "Field-induced transition of the Haldane antiferromagnets"Journal of Applied Physics. 89. 7195-7197 (2001)
[Publications] Takashi Nakanishi: "Low-Temperature Properties of Quasi-One-Dimensional Molecular-based Ferromagnets"Journal of Physical Society of japan. 70. 1380-1389 (2001)
[Publications] Atsushi Nakasu: "Field-induced gap due to four-spin exchange in a spin ladder"Journal of Physics : Condensed Matter. 13. 7421-7428 (2001)
[Publications] Toru Sakai: "Electron spin resonance absorption from the ground state of gapped spin systems"Physica Status Solidi. (2002)
[Publications] Toru Sakai: "Numerical study on pseudogap phenomena in high-Tc cuprates"Journal of Physics and Chemistry of Solids. (2002)
[Publications] Nobuhisa Okazaki: "Magnetization plateau in the S=1 spin ladder with competing interactions"Journal of Physics and Chemistry of Solids. (2002)
[Publications] Kiyomi Okamoto: "Mechanism for non-trivial magnetization plateaus of an S=1 frustrated Spin ladder"Journal of Physical Society of Japan Supplement. (2002)
[Publications] Toru Sakai: "Charge stripes based on higher-order interactions in cuprate superconductors"Physica C. (2002)
[Publications] Olivier Cepas: "Dynamics, selection rules and Dzyaloshinski-Moriya interaction in Strongly frustrated magnets"Progress of Theoretical Physics Supplement. (2002)
[Publications] Toru Sakai: "Spin flop in 1D quantum antiferromagnets"Progress of Theoretical Physics Supplement. (2002)
[Publications] Shoji Yamamoto: "Quantum phase competition in antiferromagnetic spin-i ladders"Progress of Theoretical Physics Supplement. (2002)
[Publications] 坂井徹: "ランダム初期ベクトルサンプリングを用いたランチョス法による強相関電子系の擬ギャップの研究"物性研究. 76. 890-893 (2001)
[Publications] 坂井徹: "共型場理論によるサイズスケーリングに基づく量子スピン系の磁化過程の解析"素粒子論研究. (2002)
[Publications] Hiroyuki Oyanagi: "Physics in Local Lattice Distortions"American Institute of Physics. 532 (2001)
[Publications] Jean-Paul Boucher: "Proceedings of French-Japanese Symposium "Quantum Properties of Low-Dimensional Antiferromagnets""Kyushu University Press. (2002)

2001 Fiscal Year Annual Research Report

電子スピン共鳴によるスピンギャップ直接観測の理論的研究

Principal Investigator

坂井 徹 東京都立科学技術大学, 工学部, 助教授 (60235116)

Research Products

[Publications] Toru Sakai: "Stripes due to the next-nearest neighbor exchange in high-Tc cuprates"Physical Review B. 63. 140509(R)-1-140509(R)-3 (2001)

[Publications] Toru Sakai: "Pseudogap Induced by Antiferromagnetic Spin Correlation in High-Temperature Superconductors"Journal of Physical Society of Japan. 70. 272-277 (2001)

[Publications] Toru Sakai: "Pseudo Gap and Antiferrornagnetic Spin Correlation in High-Tc Cuprates"Journal of Physics and Chemistry of Solids. 62. 203-206 (2001)

[Publications] Masayuki Hagiwara: "High Field Magnetization of an S=1/2 Zigzag Chain Compound (N_2H_5)CuCl_3"Physica B. 294-295. 83-86 (2001)

[Publications] Toru Sakai: "Selection Rule of ESR for Spin Gap Systems"Physica B. 294-295. 26-29 (2001)

[Publications] Toru Sakai: "Local Lattice distortion in High-Tc Cuprates"Journal of Synchrotron Radiation. 8. 848-850 (2001)

[Publications] Kiyomi Okamoto: "Magnetization Plateau of an S=1 Spin Ladder"Journal of Physical Society of Japan. 70. 636-639 (2001)

[Publications] Toru Sakai: "Quantum Magnetization Plateaux in Ferrimagnetic Spin Chains"Journal of Magnetism and Magnetic Materials. 226-230. 645-646 (2001)

[Publications] Toru Sakai: "Field-induced transition of the Haldane antiferromagnets"Journal of Applied Physics. 89. 7195-7197 (2001)

[Publications] Takashi Nakanishi: "Low-Temperature Properties of Quasi-One-Dimensional Molecular-based Ferromagnets"Journal of Physical Society of japan. 70. 1380-1389 (2001)

[Publications] Atsushi Nakasu: "Field-induced gap due to four-spin exchange in a spin ladder"Journal of Physics : Condensed Matter. 13. 7421-7428 (2001)

[Publications] Toru Sakai: "Electron spin resonance absorption from the ground state of gapped spin systems"Physica Status Solidi. (2002)

[Publications] Toru Sakai: "Numerical study on pseudogap phenomena in high-Tc cuprates"Journal of Physics and Chemistry of Solids. (2002)

[Publications] Nobuhisa Okazaki: "Magnetization plateau in the S=1 spin ladder with competing interactions"Journal of Physics and Chemistry of Solids. (2002)

[Publications] Kiyomi Okamoto: "Mechanism for non-trivial magnetization plateaus of an S=1 frustrated Spin ladder"Journal of Physical Society of Japan Supplement. (2002)

[Publications] Toru Sakai: "Charge stripes based on higher-order interactions in cuprate superconductors"Physica C. (2002)

[Publications] Olivier Cepas: "Dynamics, selection rules and Dzyaloshinski-Moriya interaction in Strongly frustrated magnets"Progress of Theoretical Physics Supplement. (2002)

[Publications] Toru Sakai: "Spin flop in 1D quantum antiferromagnets"Progress of Theoretical Physics Supplement. (2002)

[Publications] Shoji Yamamoto: "Quantum phase competition in antiferromagnetic spin-i ladders"Progress of Theoretical Physics Supplement. (2002)

[Publications] 坂井徹: "ランダム初期ベクトルサンプリングを用いたランチョス法による強相関電子系の擬ギャップの研究"物性研究. 76. 890-893 (2001)

[Publications] 坂井徹: "共型場理論によるサイズスケーリングに基づく量子スピン系の磁化過程の解析"素粒子論研究. (2002)

[Publications] Hiroyuki Oyanagi: "Physics in Local Lattice Distortions"American Institute of Physics. 532 (2001)

[Publications] Jean-Paul Boucher: "Proceedings of French-Japanese Symposium "Quantum Properties of Low-Dimensional Antiferromagnets""Kyushu University Press. (2002)

坂井徹東京都立科学技術大学, 工学部, 助教授 (60235116)