Crossover of Superconducting Properties and Kinetic-Energy Gain in Two-Dimensional Hubbard Model

• Yokoyama Hisatoshi

  Department of Physics, Tohoku University

• Tanaka Yukio

  Department of Applied Physics, Nagoya University

• Ogata Masao

  Department of Physics, University of Tokyo

• Tsuchiura Hiroki

  International School for Advanced Studies (SISSA)

抄録

Superconductivity in the Hubbard model on a square lattice near half filling is studied using an optimization (or correlated) variational Monte Carlo method. Second-order processes of a strong-coupling expansion are considered in wave functions beyond the Gutzwiller projection. Superconductivity of d_x²−y²-wave symmetry is widely stable, and exhibits a crossover around U=U_co∼12t from a BCS type to a new type. For U\\gtrsimU_co (U\\lesssimU_co), the energy gain in the superconducting state is derived from the kinetic (potential) energy. Condensation energy is large and ∝exp(−t⁄J) [tiny] on the strong [weak] coupling side of U_co. With reference to experiments on optical conductivity, cuprates belong to the strong-coupling regime.

収録刊行物

• Ｊｏｕｒｎａｌ　ｏｆ　ｔｈｅ　Ｐｈｙｓｉｃａｌ　Ｓｏｃｉｅｔｙ　ｏｆ　Ｊａｐａｎ

  Ｊｏｕｒｎａｌ　ｏｆ　ｔｈｅ　Ｐｈｙｓｉｃａｌ　Ｓｏｃｉｅｔｙ　ｏｆ　Ｊａｐａｎ 73 (5), 1119-1122, 2004

  一般社団法人 日本物理学会

キーワード

• superconductivity
• condensation energy
• kinetic energy
• crossover
• high-<I>T</I><SUB>c</SUB> cuprate
• Hubbard model
• variational Monte Carlo method
• optical conductivity
• antiferromagnetism

詳細情報

• CRID: 1390001204186402176
• NII論文ID: 110001954819
• NII論文ID: 130004538763
• NII論文ID: 210000104786
• NII書誌ID: AA00704814
• DOI: 10.1143/jpsj.73.1119
• BIBCODE: 2004JPSJ...73.1119Y
• ISSN: 13474073
• ISSN: 00319015
• NDL書誌ID: 6940657
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I6940657
• Web Site: http://journals.jps.jp/doi/pdf/10.1143/JPSJ.73.1119
• 本文言語コード: en
• データソース種別:
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