This volume contains the proceedings of the ffiM Japan International Sympo­ sium on Strong Correlation and Superconductivity, which was held in Keidan­ ren Guest House at the foot of Mt. Fuji, May 21-25, 1989. The purpose of the Symposium was to provide an opportunity for discus­ sions on the problem of strong correlation of electrons in the context of high-Tc superconductivity. Sixty-eight scientists were invited from seven countries and forty-three papers were presented in the Symposium. Soon after the discovery ofhigh-Tc superconducting oxides, Professor P. W. Anderson proposed that the essence of high-Tc superconductivity lies in the strong correlation among the electrons in these materials. This proposal has stimulated a wide range of theoretical investigations on this profound and dif­ ficult problem, which are expected to lead eventually to new concepts describ­ ing strong electron correlation. In the Symposium, Anderson himself started lively discussions by his talk entitled "Myth and Reality in High-Tc Supercon­ ductivity", which was followed by various reports on theoretical studies and experimental results. Concise and thoughtful summaries of experiment and theory were given by Professors H. R. Ott and P. A. Lee, respectively. It is our hope that this volume reflects the present status of the research activity on this outstanding problem from the viewpoint of the basic physics and that it will further stimulate the effort to understand these fascinating systems, the high-Tc oxides.

Inhalt

I Overview.- Myth and Reality in High-Tc Superconductivity.- II Theory.- Recent Advances in the Stability and Properties of Commensurate Flux Phases.- U(1) Gauge Field, t'-J Model and Superconductivity.- Spectroscopic and Theoretical Estimates of Parameters in Model Hamiltonians Describing the High and Low Energy Scale Physics of Doped CuO2 Planes.- Effective Hamiltonian for High-Tc Cu Oxides.- The Madelung Energy of Cu-O Based Compounds.- Electronic Properties in the Cu-Oxide Superconductors.- Core-Level Spectroscopy in High-Tc Superconducting Materials.- Dispersive Single-Particle Excitations in Strongly Correlated Two-Dimensional Systems.- Magnetism and Superconductivity in Strongly Correlated Systems in One and Two Dimensions.- Characteristics of the Charged Hole in the One-Dimensional Mott Insulator.- On the Application of Projection Techniques to the Electron Correlation Problem.- Slave-Fermion Mean Field Theory of the Hubbard Model.- Disorder and Interactions in the Hubbard Model.- Characteristic Features of Electronic States in High-Tc Superconducting Oxides.- Anderson Lattice Model of High-Tc Superconductors.- Quasi-Particles in the Degenerate Lattice Anderson Model.- Experimental Constraints and Theory of Layered High-Tc Superconductors.- III Experiments.- Physical Properties of High-Tc Oxide Superconductors - Effect of Doping on the Electronic State.- Andreev Reflection, Thermal Conductivity, Torque Magnetometry, and Hall Effect Studies on High-Tc Systems.- Resistive State and Hall Effect in High-Tc Superconductors.- Raman Probing of Electronic Gap Excitations and Their Coupling to Phonons in High-Tc Superconductors.- Magnetic Correlations in High-Tc Oxides in the Superconducting State.- NMR Studies of YBa2Cu3O7?? (Tc = 90 K).- NMR and NQR in Highly Correlated Metallic and Superconducting Cu Oxides.- NMR Study of High-Tc Superconductors.- Tunneling Spectroscopy and Energy Gap of High-Tc Oxide Superconductors.- Optical Absorption in La2?xSrxCuO4 Epitaxial Thin Films.- Infrared Studies of Oxide Superconductors in the Normal and Superconducting States.- Nature of the Electronic States Near the Fermi Level in High-Tc Superconductors: High-Energy Spectroscopic Evidence.- Photoemission, Inverse Photoemission and X-Ray Absorption Spectroscopies of Bi2Sr2CaCu2O8.- A New Family of High-Tc Superconductors: (Ln1?xCex)2(Ba1?yLny)2Cu3O10?z (Ln: Nd, Sm, Eu and Gd).- Magnetic Interactions in High-Tc Superconductors and Related Oxides.- Physical Properties of (Ba,K)BiO3.- Flux Creep and the Crossover to Flux Flow in the Resistivity of High-Tc Superconductors.- Giant Fluctuation Model and the Field-Induced Broadening of the Superconducting Transition in Oxides.- Flux Dynamics and Electronic Anisotropy in High-Tc Superconductors.- IV Summary.- Summary Talk: Experimental.- Summary Talk: Theory.- V Abstracts.- Recent Numerical Results on the Two-Dimensional Hubbard Model.- Valence Bond and Spin-Peierls Ground States of Low-Dimensional Quantum Antiferromagnets.- Holes in Copper Oxides: Where Are They? How Do They Conduct? How Do They Affect Superconductivity?.- Optical Excitations in CuO2 Sheets With and Without Electron Doping: Relevance to Superconductivity Produced by Electron Doping.- Experimental Observations on Superconducting Single Crystals.- Index of Contributors.