Although the problem of a metal in one dimension has long been known to solid-state physicists, it was not until the synthesis of real one-dimensional or quasi-one-dimensional systems that this subject began to attract considerable attention. This has been due in part to the search for high­ temperature superconductivity and the possibility of reaching this goal with quasi-one-dimensional substances. A period of intense activity began in 1973 with the report of a measurement of an apparently divergent conduc­ tivity peak in TfF-TCNQ. Since then a great deal has been learned about quasi-one-dimensional conductors. The emphasis now has shifted from trying to find materials of very high conductivity to the many interesting problems of physics and chemistry involved. But many questions remain open and are still under active investigation. This book gives a review of the experimental as well as theoretical progress made in this field over the last years. All the chapters have been written by scientists who have established themselves as experts in theoreti­ cal and experimental solid-state physics. The book is intended to be of use both to students and researchers entering the field as well as to more advanced physicists. The wealth of ideas and information it contains ought to be useful to anyone interested in quasi-one-dimensional systems, organic solids, or the search for novel conduction and superconduction mechanisms. The editors are very grateful to the authors for their collaboration in this book.

Inhalt

1 Introduction to Highly Conducting One-Dimensional Solids.- 1. Introduction.- 2. Some Preliminary Thoughts.- 3. Excitonic Superconductivity.- 4. TCNQ Salts and KCP.- 4.1. NMP-TCNQ.- 4.2. TTF-TCNQ.- 4.3. KCP.- 5. TTF-TCNQ and TSeF-TCNQ.- 5.1. Structural Transitions in TTF-TCNQ.- 5.2. Electromagnetic Properties of TTF-TCNQ.- 5.3. ESR and Alloys of TTF-TCNQ and TSeF-TCNQ.- 6. Theory.- 7. Some Concluding Thoughts.- References.- 2 X-Ray and Neutron Scattering from One-Dimensional Conductors.- 1. Introduction.- 1.1. Lattice Instabilities and Phonon Anomalies.- 1.2. X-Ray Diffuse Scattering.- 1.3. Neutron Scattering.- 2. Structural Studies of KCP and Related Platinum Chain Complexes.- 2.1. Structure and One-Dimensional Electrical Properties of KCP.- 2.2. X-Ray Diffuse Scattering from KCP.- 2.3. Neutron Scattering Studies of KCP.- 2.4. Study of Other Platinum Complexes.- 3. Structural Studies of Organic One-Dimensional Conductors.- 3.1. Structure and TTF-TCNQ Crystals.- 3.2. High-Temperature Precursor Scattering in TTF-TCNQ.- 3.3. The Modulated Phases of TTF-TCNQ.- 3.4. Spin Waves in TTF-TCNQ?.- 3.5. The Interpretation of the Sequence of Modulated Phases in TTF-TCNQ.- 3.6. Study of Other Organic One-Dimensional Conductors.- 4. Concluding Remarks.- References and Notes.- 3 Charge-Density Wave Phenomena in One-Dimensional Metals: TTF-TCNQ and Related Organic Conductors.- 1. Introduction.- 2. Strength of Interactions; Bandwidth, Electron-Electron and Electron-Phonon Interactions.- 2.1. One-Electron Energies; Band Structure.- 2.2. Electron-Electron Interactions: Nuclear Magnetic Resonance and Magnetic Susceptibility.- 2.3. Electron-Phonon Interaction.- 3. The Peierls Instability in TTF-TCNQ: Structural Aspects and Phonon Softening.- 4. The Pseudogap: Optical Properties.- 5. Electrical Conductivity.- 5.1. DC Measurements.- 5.2. Microwave Measurements.- 6. The Transition Region 38°K<TTc1.- 4.1. Transport Properties.- 4.2. Magnetic Properties.- 4.3. Phonon Anomalies.- 5. Metal-Semiconductor Phase Transition.- 5.1. Variation of Transition Temperature Tc1 with Alloying.- 5.2. Thermodynamics and Critical Behavior of the Metal-Semiconductor Phase Transition.- 6. Semiconducting Phase, T< Tc1.- 6.1. Transport Properties in the Semiconducting Phase.- 6.2. Magnetic Properties.- 6.3. Superlattices and Phonon Anomalies.- 7. Summary.- References and Notes.- 5 Perturbation Approach to Lattice Instabilities in Quasi-One-Dimensional Conductors.- 1. Introduction.- 2. The One-Dimensional Electron-Phonon System.- 3. Fluctuations in the One-Dimensional System.- 4. Effects of Interchain Coupling.- 5. Effects of Impurities.- References and Notes.- 6 Theory of the One-Dimensional Electron Gas.- 1. Basic Physics.- 1.1. Introduction.- 1.2. Phase Transitions and Long-Range Order.- 1.3. Mathematical Model.- 1.4. Strong Coupling.- 2. Spinless Fermions.- 2.1. Definition of the Continuum Limit.- 2.2. Boson Representations and the Free Energy.- 2.3. Boson Representations of Fermion Fields.- 2.4. Correlation Functions of the Interacting System.- 3. Large "On-Site" Interaction.- 3.1. Attractive Interaction.- 3.2. Repulsive Interaction.- 3.3. Correlation Functions.- 4. Continuum Limit-Energy Gaps.- 4.1. Separation of Charge and Spin Degrees of Freedom.- 4.2. Reduction to Spinless Fermions.- 4.3. Solution of the Spinless Fermion Problems.- 4.4. Correlation Functions.- 4.5. Relationship to Other Problems.- 5. Renormalization Group Method.- 5.1. Scaling Equations.- 5.2. Trajectories and Energy Scales.- 5.3. Low-Temperature Properties.- 5.4. Four-Particle Functions.- Appendix A: Some Results That Are Useful for Working with Boson Representations.- Appendix B: Anticommutation of Different Fermion Fields.- Appendix C: Charge-Density Wave Gap and CDW Correlations.- References.- 7 The Prospects of Excitonic Superconductivity.- 1. Introduction.- 2. The Nature of Superconductivity.- 2.1. Background.- 2.2. Phonon Mechanism.- 2.3. Limitation on Tc.- 2.4. Isotope Effect.- 2.5. Exciton Mechanism.- 3. Problems of Superconductivity Unique to the Exciton Mechanism.- 3.1. Exchange.- 3.2. Apparent Limitation on ???*.- 3.3 Vertex Corrections.- 3.4. Equation for Tc.- 3.5. The Kernel U(p, k).- 3.6. Effects of the Phonons on the Exciton Mechanism.- 4. Effects of Limited Dimensionality.- 4.1. Effects of Fluctuations.- 4.2. Types of Order in a One-Dimensional Electron Gas.- 4.3. Relevance of g-ology.- 4.4. Interchain Coupling.- 4.5. Localization and Impurities.- 4.6. Effects of Screening.- 5. Real Models.- 5.1. Model of a Filamentary Excitonic Superconductor.- 5.2. Discussion.- 6. Summary.- References.- 8 Recent Developments and Comments.- 1. Introduction.- 2. Nature of the Phase Transitions.- 2.1. Transition in KCP.- 2.2. Transitions in TCNQ Compounds.- 2.3. Transitions in TaS3, NbSe3.- 3. Coulomb Interactions and Magnetic Susceptibility.- 3.1. Limitations of the Hubbard Model.- 3.2. Magnetic Susceptibility.- 3.3. Problem of TTF-TCNQ.- 3.4. Properties of NMP-TCNQ.- 4. Collective Transport.- 4.1. Superconductivity and One-Dimensional Fluctuations.- 4.2. Dielectric Properties.- 4.3. Transport above Tc.- 4.4. Nonlinear Field Dependence of Conductivity.- 5. Concluding Comments.- References.- Author Index.