The metal-insulator transition due to electron-electron interactions is one of the most celebrated but least understood problems in condensed matter physics. Here this subject is comprehensively reviewed for the first time since Sir Nevill Mott's monograph of 1990. A pedagogical introduction to the basic concepts for the Mott transition, the Hubbard model, and various analytical approaches to correlated electron systems is presented. A new classification scheme for Mott insulators as Mott-Hubbard and Mott-Heisenberg insulators is proposed. Traditional methods are critically examined for their potential to describe the Mott transition. This book will make an excellent reference for scientists researching in the field of electron transport in condensed matter.

Klappentext

Little do we reliably know about the Mott transition, and we are far from a complete understanding of the metal --insulator transition due to electr- electron interactions. Mott summarized his basic ideas on the subject in his wonderful book Metal--Insulator nansitions that first appeared in 1974 11. 1). In his view, a Motk insulator displays a gap for charge-carrying excitations due to electron cowelations, whose importance is expressed by the presence of local magnetic moments regardless of whether or not they are ordered. Since the subject is far from being settled, different opinions on specific aspects of the Mott transition still persist. This book naturally embodies my own understanding of the phenomenon, inspired by the work of the late Sir Kevill Mott. The purpose of this book is twofold: first, to give a detailed presen- tion of the basic theoretical concopts for Mott insulators and, second, to test these ideas against the results from model calculations. For this purpose the Hubbard model and some of its derivatives are best suited. The Hubbard model describes a Mott transition with a mere minimum of tunable par- eters, and various exact statements and even exact solutions exist in certain limiting cases. Exact solutions not only allow us to test our basic ideas, but also help to assess the quality of approxin~ate theories for correlated electron systems.

Inhalt

Metal-Insulator Transitions.- Hubbard Model.- Approximate Methods.- One-Dimensional Hubbard Models.- Hubbard Model in Infinite Dimensions.- Further Models with Hubbard Interaction.- Conclusions.