| Co-Investigator(Kenkyū-buntansha) |
LEE P.A Department of Physics, Massachusetts Institute of Technology, 教授
SCALAPINO D.J Department of Physics, University of California, 教授
COLEMAN P Serin Physics Laboratory, Rutgers University, 助教授
DAGOTTO E Physics Department and National High Magnetic Field Laboratory, Florida State Un, 助教授
RICE T.M ETH-Honggerberg, Theoretische Physik, 教授
吉岡 大二郎 東京大学, 大学院・総合文化研究科, 教授 (30114713)
三宅 和正 大阪大学, 基礎工学部, 教授 (90109265)
福山 秀敏 東京大学, 大学院・理学系研究科, 教授 (10004441)
NAGAOSA N Department of Applied Physics, University of Tokyo, 大学院・工学系研究科, 教授 (60164406)
KURAMOTO Y Department of Physics, Tohoku University, 大学院・理学研究科, 教授 (70111250)
KAWAKAMI N Department of Material and Life Science, and Department of applied physics, Osak, 大学院・工学研究科, 教授 (10169683)
小形 正男 東京大学, 大学院・総合文化研究科, 助教授 (60185501)
上田 和夫 東京大学, 物性研究所, 教授 (70114395)
今田 正俊 東京大学, 物性研究所, 助教授 (70143542)
YOSHIOKA D Institute of Physics, College of Arts and Science, University of Tokyo
MIYAKE K Department of Material Physics, Osaka University
FUKUYAMA H Department of Physics, University of Tokyo
OGATA M Institute of Physics, College of Arts and Science, University of Tokyo
IMADA M Institute of solid state physics, University of Tokyo
UEDA K Institute of Solid State Physics, University of Tokyo
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| Research Abstract |
Electronic excitations in low-dimensional strongly correlated systems have attracted considerable attention since the discocvery of high temperature superconductors. In the one-dimensional (1D) systems, it is known that the spin-charge separation occurs and the spin and charge degress of freedom of electrons obey the different dynamics. The elementary excitations of spin and charge are called spinons and holons, respectively. The nature of spin and charge degrees of freedom in the two-dimensional (2D) systems is one of the central issues in the study of high temperature superconductors. Recent advances in angle-resolved photoemission spectroscopy (ARPES) offers an opportunity of testing the theory of the strongly correlated systems.
We have studied the single-particle, spin and charge excitations in strongly correlated low-dimensional systems by using the analytical as well as numerical methods. The single-particle spectrum at half-filling is in accord with the recent angle-resolved photoemission spectrum in the 1D cuprate SrCuO_2 and is in strong contrast with that in the 2D one Sr_2CuO_2Cl_2. In 2D,the behaviors of these excitation spectra are strongly dependent on electron concentration. Far away from half-filling, the single-particle spectrum includes both spin and charge excitations as expected in a Fermi liquid. On the other hand, near half-filling, the apectra are rather similar to those in 1D,indicating that the charge and spin degrees of freedom obey the different dynamics.
Our study offers a basis of the new quantum theory of solids which starts with the internal degrees of freedom of electrons.
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