Research activities in low dimensional conductors have shown a rapid growth since 1972 and have led to the discovery of new and remarkable phy sical properties unique to both molecular and inorganic conductors exhibi ting one-dimensional transport behaviour. This NATO Institute was a conti nuation of aseries of NATO Advanced Study Institutes of Worshops which took place at regular intervals till 1979. This is the first time, however, that charge density wave transport and electronic properties of low dimen sional organic conductors are treated on an equal footing. The program of the Institute was framed by tutorial lectures in the theories and experiments of low dimensional conductors. The bulk of the course covered two series of low-dimensional mate rials with their respective properties. 1) The I-D inorganic conductors exhibiting the phenomena of sliding charge density waves, narrow band noise, memory effects, etc ..• 2) Low-dimensional crystallized organic conductors giving rise to various possibilities of ground states, spin-Peierls, spin density wave, Peierls, superconductivity and magnetic-field induced spin density wave, etc ... Since it has been established from the beginning that this Institute was to be devoted essentially to the Physics of Low Dimensional Conductors, only one main course summarized the progress in chemistry and material preparation.

Advances in the physics and chemistry of low-dimensional systems have been really magnificent in the last few decades. Hundreds of quasi-one-dimensional and quasi-two-dimensional systems have been synthesized and studied. The most popular representatives of quasi-one-dimensional materials are polyacethylenes CH [1] and conducting donor-acceptor molecular crystals TIF z TCNQ. Examples of quasi-two-dimensional systems are high temperature su perconductors (HTSC) based on copper oxides LA2CU04, YBa2Cu306+y and organic superconductors based on BEDT -TIP molecules. The properties of such one- and two-dimensional materials are not yet fully understood. On the one hand, the equations of motion of one-dimensional sys tems are rather simple, which facilitates rigorous solutions of model problems. On the other hand, manifestations of various interactions in one-dimensional systems are rather peculiar. This refers, in particular, to electron--electron and electron-phonon interactions. Even within the limit of a weak coupling con stant electron--electron correlations produce an energy gap in the spectrum of one-dimensional metals implying a Mott transition from metal to semiconductor state. In all these cases perturbation theory is inapplicable. Which is one of the main difficulties on the way towards a comprehensive theory of quasi-one-dimensional systems. - This meeting held at the Institute for Theoretical Physics in Kiev May 15-18 1990 was devoted to related problems. The papers selected for this volume are grouped into three sections.

The field of low-dimensional conductors has been very active for more than twenty years. It has grown continuously and both the inorganic and organic materials have remark able properties, such as charge and spin density waves and superconductivity. The discovery of superconductivity at high temperature in copper-based quasi two-dimensional conducting oxides nearly ten years ago has further enlarged the field and stimulated new research on inorganic conductors. It was obviously impossible to cover such a broad field in a ten day Institute and it seemed pertinent to concentrate on inorganic conductors, excluding the high Tc superconducting oxides. In this context, it was highly desirable to include both physics and chemistry in the same Institute in order to tighten or in some cases to establish links between physicists and chemists. This Advanced Study Institute is the continuation of a series of similar ones which have taken place every few years since 1974. 73 participants coming from 13 countries have taken part in this School at the beautiful site of the Centre de Physique des Houches in the Mont-Blanc mountain range. The scientific programme included more than forty lectures and seminars, two poster sessions and ten short talks. Several discussion sessions were organized for the evenings, one on New Materials, one on New Topics and one on the special problem of the Fermi and Luttinger liquids. The scientific activity was kept high from the beginning to the end of the Institute.

This book is a printed edition of the Special Issue "Advances in Organic Conductors and Superconductors" that was published in Crystals

This book explores the relationship between electronic correlations, dimensionality, inhomogeneities, and superconductivity in low-dimensional systems by studying single crystals of the quasi-one-dimensional Na2–δMo6Se6, composed of MoSe filaments weakly coupled by Na atoms and subject to intrinsic disorder (δ > 0). It shows that the Na2-δMo6Se6 displays strong electronic correlations in its normal state, whereas a superconducting ground state emerges from Anderson localized electrons. Two novel behaviors of the superconducting state are observed: first, a disorder induced enhancement of the superconducting transition temperature; second, a reentrant phase coherence with increasing temperature, magnetic field, and current. It also analyzes the intrinsic properties of Na2-δMo6Se6 are analyzed to offer a thorough understanding of these phenomena. The emergence of superconductivity in such low-dimensional systems provides a fruitful playground to explore electronic order and correlations.

List of Contributors: P W Anderson, S Tanaka, C W Chu, Y H Kim, T V Ramakrishnan, G Wendin, G Baskaran, H Fukuyama, Y Hasegawa, A Zawadowski, A A Abrikosov, A I Buzdin, V L Ginzburg, S Barisic, I Batistic, E J Mele, L Dzyaloshinskii, L A Falkovsky, J R Schrieffer, D J Scalapino, A I Larkin, K W Becker, P Fulde, S A Trugman, F C Zhang, K A Chao, G Z Wei, D JŽrome et al., J Bardeen, M Sinclair, S M Girvin, D P Arovas, P B Wiegmann and others.

This book is addressed to all scientists interested in the use of high magnetic ?elds and in the use of high-?eld facilities around the world. In particular it will help young scientists and newcomers to the topic to gain a better understanding in areas such as condensed matter physics, in which the magnetic ?eld plays a key role either as a parameter controlling the Hamiltonian, or as an experimental tool to probe the underlying mechanism. This concerns mostly strongly correlated and (or) low dimensional systems. Rather than covering all these subjects in detail, the philosophy here is to give essential physical concepts in some of the most active ?elds, which have been quickly growing in the last ten to twenty years. Besides its role as a physical parameter in condensed matter physics, a large magnetic ?eld is essential to Electron Paramagentic Resonance (EPR) and Nuclear Magnetic Resonance (NMR) spectroscopies. The state of art of high resolution NMRin liquids and solids and high frequency EPRapplied to ?elds like chemistry and biology are also reviewed in this volume. The ?rst series of chapters is devoted to the integer and the Fractional Qu- tum Hall E?ects (FQHE) in two-dimensional electron systems. C. Glattli brushes an historical background and a comprehensive review of transport phenomena in these systems, including recent developments on the mesoscopic electronic transport at the edges of quantum Hall samples, chiral Luttinger liquids and fractional excitations. R.

The book covers different aspects of the chemistry and physics of molecular materials, including organic synthesis of specific organic donors and ligands, organic metals and superconductors, molecule-based magnets, multiproperty materials and organic-inorganic hybrids. The 17 chapters are written by some of the most authoritative authors in their field. The two last chapters are devoted to molecular electronics and devices, in particular the achievements and potential for applications. An excellent work for all students and researchers in organic conductors, superconductors and molecule based magnets.

Frontiers in Superconducting Materials gives a state-of-the-art report of the most important topics of the current research in superconductive materials and related phenomena. It comprises 30 chapters written by renowned international experts in the field. It is of central interest to researchers and specialists in Physics and Materials Science, both in academic and industrial research, as well as advanced students. It also addresses electronic and electrical engineers. Even non-specialists interested in superconductivity might find some useful answers.

This bang up-to-date volume contains the distilled wisdom of some of the world’s leading minds on the subject. Inside, there is a treasure trove of general (tutorial) and topical reviews, written by leading researchers in the area of organic superconductors and conductors. The papers hail from all over the world, as far afield as the USA and Australia. They cover contemporary topics such as unconventional superconductivity, non-Fermi-liquid properties, and the quantum Hall effect.