Solid State Physics

This textbook has developed from the experience of the authors in teaching the course
of SoHd State Physics to students in physics at the Universities of Pavia and Pisa.
The book is addressed to students at the graduate and advanced level, both oriented
toward theoretical and experimental activity. No particular prerequisite is required,
except for the ordinary working knowledge of wave mechanics. The degree of difficulty
increases somewhat as the book progresses; however, the contents develop always in
very gradual steps.
The material presented in the book has been assembled to make as economical as
possible the didactical task of teaching, or learning, the various subjects. The general
organization in chapters, and groups of chapters, is summarized in the synoptic table
of contents. The first three chapters have a propaedeutic natinre to the main entries of
the book. Chapter IV starts with the analysis of the electronic structure of crystals,
one of the most traditional subjects in solid state physics; chapters V and VI concern the band theory of soUds and a number of specific applications; the concepts of
excitons and plasmons are given in chapter VII. Then, in chapters VIII and DC, the
adiabatic principle and the interdependence of electronic states and lattice dynamics
are studied. Having established the electronic and vibrational structure of crystals, the
successive chapters from X to XIV describe several investigative techniques of crystaUine properties; these include scattering of particles, optical spectroscopy, and transport measurements. Chapters XV, XVI and XVII concern the electronic magnetism
of tendentially delocalized or localized electronic systems, and cooperative magnetic
effects. The final chapter is an introduction to the world of superconductivity.
Prom a didactical point of view, an effort is made to remain as rigorous as possible,
while keeping the presentation at an accessible level. In this book, on one hand we
aim to give a clear presentation of the basic physical facts, on the other hand we wish
to describe them by rigorous theoretical and mathematical tools. The technical side
is given the due attention and is never considered optional; in fact, a clear supporting
theoretical formalism (without being pedantic) is essential to establish the limits of
the physical models, and is basic enough to allow the reader eventually to move on
his or her own legs, this being the ultimate purpose of a useful book.
The various chapters are organized in a self-contained way for the contents, appendixes (if any), references, and have their own progressive numeration for tables,
figures and formulae (the chapter number is added when addressing items in chapters
differing from the running one). With regards to the references, these are intended
only as orientative, since it is impossible to mention, let alone to comment on, all
the relevant contributions of the wide literature. Since the chapters are presented in a
(reasonably) self-contained way, the lecturers and readers are not compelled to follow
the order in which the various subjects are discussed; the chapters, or group of chapters, can be taken up with great flexibility, selecting those topics that best fit personal
tastes or needs. We will be very interested and very pleased to receive (either directly
or by correspondence) comments and suggestions from lecturers and readers.
The preparation of a textbook, although general in nature, requires also a great
deal of speciahzed information. We consider ourselves fortunate for the generous help
of the colleagues and friends at the Physics Departments of the University of Pavia,
University of Pisa, and Scuola Normale Superiore of Pisa; they have contributed to
making this textbook far better by sharing their expertise with us. Very special thanks
axe due to Emilio Doni, who survived the task of reading and commenting on the
whole preview-manuscript. Several other colleagues helped with their critical reading
of specific chapters; we are particularly grateful to Lucio Claudio Andreani, Antonio
Barone, Pietro Carretta, Alberto Di Lieto, Giorgio Guizzetti, Franco Marabelli, Liana
MartinelU, Attilio Rigamonti. Many heartfelt thanks are due to Saverio Moroni for his
right-on-target comments.
Before closing, we wish to thank all contributors and publishers, who gave us permission to reproduce their illustrations; their names and references are indicated adjacent
each figure. We wish also to express our gratitude to Gioia Ghezzi for her encouragement, to Serena Bureau, Manjula Goonawardena, Cordelia Sealy and Bridget Shine
for their assistance in the preparation of the manuscript. Last, but always first, we
thank om* families for their never ending trust that the manuscript would eventually
be completed and would be useful to somebody