| Project/Area Number |
11640333
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | University of Tsukuba |
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Principal Investigator |
TSUNETSUGU Hirokazu University of Tsukuba, Institute of Materials Science, Associate Professor, 物質工学系, 助教授 (80197748)
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| Co-Investigator(Kenkyū-buntansha) |
MOTOME Yukitoshi University of Tsukuba, Institute of Materials Science, Research Associate, 物質工学系, 助手 (40323274)
SHIBATA Nokazu University of Tokyo, Institute of Physics, Research Associate, 大学院・総合文化研究科, 助手 (40302385)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1999: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | strongly correlated electrons / numerical diagonalization / quantum Monte Carlo simulation / DMRG / Kondo lattice model / parallel computer / t-J model / double exchange model / 数値計算 / 動的相関関数 / スピン励起 / ラッティンジャー液体 / t―J模型 |
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| Research Abstract |
In this research project, we have performed large-scale numerical study on the ground state and thermodynamic properties of strongly correlated electron systems. Parallel computers with several hundreds of nodes, supercomputers with high vectorization performance, and workstation clusters are used to carry on various types of numerical simulations. Summary of the obtained results is the following.
The one-dimensional Kondo lattice model is studied by the density-matrix renormalization-group method. We have calculated the dynamic correlation function of local spin and charge correlations for the hole doped case. We find small new energy scales upon hole doping, and we discuss the relationship between these energy scales and collective excitations in the luttinger-liquid ground state. We also demonstrate the competition between the RKKY interaction of local spins and the Kondo screening due to itinerant electrons, based on the results of the antiferromagnetic spin susceptibility.
We have calculated the single-electron spectrum and pairing correlations in the two-dimensional t-J model, to study the correlation of (π, 0) level and the d-wave superconductivity. We show that the superconductivity could be enhanced by level tuning of the (π, 0) level to the Fermi energy by artificial design of electron hoppings.
We have performed the quantum Monte-Carlo parallel simulations on the three-dimensional double exchange model using large-scale workstation/PC clusters. The critical exponent of ferromagnetic transition in this model is determined.
We have developed and improved various routines and tools for parallelized numerical diagonalization of the t-J model.
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