This volume contains the proceedings of the Eighth Taniguchi Interna tional Symposium on the Theory of Condensed Matter, which was held at Shima Kanko Hotel in Shima, Japan, 10-13 April 1985. The topic of the Symposium was Valence Fluctuation and Heavy Fermion Systems, one of the most fundamental problems in present-day condensed matter physics. The dilute Kondo problem, which is one of the most typical and unique many-body problems in condensed matter physics, developed recently into the dense Kondo and the coherent Kondo lattice problems in the 4f elec tron systems. It is accepted now that a large degeneracy in f-electron systems makes this latter situation possible by enhancing the single-site Kondo state relative to the inter-site magnetic interactions. Now, anoma lous behavior in f-electron systems show rich variety and are called valence fluctuation phenomena as a whole. They have, however, a common fea ture. In the lowest temperature region, they show either heavy Fermion like character or a narrow gap formation at the Fermi energy. Discovery of superconductivity in the heavy Fermion systems is attracting more in terest. Anyway, the valence fluctuating states are thought to be of fun damental importance to bridge the gap between the localized magnetic states and the delocalized nownagnetic states.

During the Koln meeting (August 28-31, 1984), Irdia was chosen as the venue for the next International Conference on Valence Fluctuations. lhis was in recognition ard appreciation of the work done, both experimental ard theoretical, by the Irdian scientists in this area during the last decade. We decided to hold this Conference in the month of January, 1987 at Bangalore. lhe subject of Valence Fluctuations has kept itself alive ard active as it has provided many shocks ard suprises particularly among the Ce- ard U-based intermetallies. lhe richness of many interesting physical phenomena occurring in mixed valent materials, the flexibility of modifying their physical properties (by alloying, for example) ard the possibility of synthesizing a wide variety of new such materials seem to be the key factors in this regard. Barely six months before this Conference, an International Conference on Anomalous Rare Earths and Actinides (ICAREA) had been held at Grenoble (July, 1986) which also focussed on mixed valence ard heavy fermion phenomena. In spite of this, the response to this' Conference was very enthusiastic and encouraging. Many interesting ard important results were presented at this Conference which have been included in this volume.

Monte Carlo Simulation in Statistical Physics deals with the computer simulation of many-body systems in condensed-matter physics and related fields of physics, chemistry and beyond, to traffic flows, stock market fluctuations, etc.). Using random numbers generated by a computer, probability distributions are calculated, allowing the estimation of the thermodynamic properties of various systems. This book describes the theoretical background to several variants of these Monte Carlo methods and gives a systematic presentation from which newcomers can learn to perform such simulations and to analyze their results. This fourth edition has been updated and a new chapter on Monte Carlo simulation of quantum-mechanical problems has been added. To help students in their work a special web server has been installed to host programs and discussion groups (http://wwwcp.tphys.uni-heidelberg.de). Prof. Binder was the winner of the Berni J. Alder CECAM Award for Computational Physics 2001.

Extensive studies of high-Tc cuprate superconductors have stimualted investigations into various transition-metal oxides. Mott transitions in particular provide fascinating problems and new concepts in condensed matter physics. This book is a collection of overviews by well-known, active researchers in this field. It deals with the latest developments, with particular emphasis on the theoretical, spectroscopic, and transport aspects.

Self-Trapped Excitons discusses the structure and evolution of the self-trapped exciton (STE) in a wide range of materials. It includes a comprehensive review of experiments and extensive tables of data. Emphasis is given throughout to the unity of the basic physics underlying various manifestations of self-trapping, with the theory being developed from a localized, atomistic perspective. The topics treated in detail in relation to STE relaxation include spontaneous symmetry breaking, lattice defect formation, radiation damage, and electronic sputtering.

Several years have passed since the first edition of this book was published. During this period, significant developments in the study of electron systems have taken place, especially in the areas ofhigh-Tc superconductivity and the quantized Hall effect. These developments, and such fascinating subjects as crystallization and the stability of matter are included in the second edition. Bardstown, KY A.Isiham June 1997 Preface to the First Edition The study of electronic properties reveals a common basis for a variety of sys tems, including gaseous plasmas, ionic solutions, metals, and semiconductors. This study started with one-electron properties in free space, as discussed in solid-state books. However, significant progress has been made recently in more realistic and complicated cases with interactions, confinements, impu rities, and fields. Moreover, the recent discoveries of the quantum Hall effect, high-Tc superconductors, and localization phenomena, along with the intr~ duction of low-dimensional materials have opened new areas and have led to a tremendous number of articles in existing journals and even new specialized journals. This book has been written to provide a new, comprehensive review on electronic properties in such diverse areas and materials.

This text presents an overview of the electronic transport phenomena including high-Tc superconductivity and colossal magnetoresistance. It concisely reviews all the conducting oxides, discussing in detail nine representative oxides. More than 1200 references serve as a convenient guidepost to proceed into this vast research field.

The experimental discovery of the fractional quantum Hall effect (FQHE) at the end of 1981 by Tsui, Stormer and Gossard was absolutely unexpected since, at this time, no theoretical work existed that could predict new struc tures in the magnetotransport coefficients under conditions representing the extreme quantum limit. It is more than thirty years since investigations of bulk semiconductors in very strong magnetic fields were begun. Under these conditions, only the lowest Landau level is occupied and the theory predicted a monotonic variation of the resistivity with increasing magnetic field, depending sensitively on the scattering mechanism. However, the ex perimental data could not be analyzed accurately since magnetic freeze-out effects and the transitions from a degenerate to a nondegenerate system complicated the interpretation of the data. For a two-dimensional electron the positive background charge is well separated from the two gas, where dimensional system, magnetic freeze-out effects are barely visible and an analysis of the data in the extreme quantum limit seems to be easier. First measurements in this magnetic field region on silicon field-effect transistors were not successful because the disorder in these devices was so large that all electrons in the lowest Landau level were localized. Consequently, models of a spin glass and finally of a Wigner solid were developed and much effort was put into developing the technology for improving the quality of semi conductor materials and devices, especially in the field of two-dimensional electron systems.

Photoelectron Spectroscopy presents an up-to-date introduction to the field by comprehensively treating the electronic structures of atoms, molecules, solids, and surfaces. Brief descriptions are given of inverse photoemission, spin-polarized photoemission and photoelectron diffraction. Experimental aspects are considered throughout the book and the results are carefully interpreted in terms of the theory. A wealth of measured data is presented in tabulator form for easy use by experimentalists.