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Modulated crystals have been intensively investigated over the past several years and it is now evident that an understanding of their crystallography and microstructure is fundamental to the elucidation of the physical properties and phase transitions in these materials. This book brings together for the first time the crystallographic descriptions and experimental methods for the structural and microstructural analysis of modulated crystals as described by well-known researchers in the various areas. The emphasis is on charge density wave modulations, and the detailed analysis of the prototypical NbTe4/TaTe4 system gives practical applications of the methods. Scanning Tunnelling Microscopy is a new technique providing significant new insights into atomic scale details of the modulations' structures and a chapter on this method is included.
List of contents
Alternative Approaches to the Crystallographic Description of Charge Density Wave Modulated Systems.- 1. Introduction.- 2. The Symmetry Description of Modulated Structures.- 3. Applications.- 4. Concluding Remarks.- References.- X-ray Crystallographic Analysis of the Charge Density Wave Modulated Phases in the NbTe4 - TaTe4System.- 1. Introduction.- 2. Modulations.- 3. Phase Transitions.- 4. Structures.- References.- Charge Density Wave Phase Transitions and Microstructures in the TaTe4 - NbTe4 System.- 1. Introduction.- 2. Transmission Electron Microscopy of CDW Phase Transitions.- 3. CDW Phase Transitions in the Transition Metal Tetrachalcogenides TaTe4-NbTe4.- 4. Concluding Remarks.- References.- Transmission Electron Microscopy of CDW-Modulated Transition Metal Chalcogenides.- 1. Introduction.- 2. Selected Area Diffraction.- 3. Convergent Beam Diffraction.- 4. Satellite Dark Field Microscopy.- 5. High Resolution Electron Microscopy.- References.- Influence of Defects and Impurities on Charge Density Wave Systems.- 1. Introduction.- 2. Point Defects in CDW Materials.- 3. CDW in the Presence of Defects.- 4. Structural Variations in the Pinned CDW.- 5. Local Perturbations of the CDW.- 6. The Microstructural Aspect of the Pinning Strength.- 7. Conclusion.- References.- Analysis of Scanning Tunneling and Atomic Force Microscopy Images.- 1. Introduction.- 2. Simulations of STM and AFM Images.- 3. STM and AFM Images of Several Layered Compounds.- 4. Concluding Remarks.- References.- Elucidating Complex Charge Density Wave Structures in Low-Dimensional Materials by Scanning Tunneling Microscopy.- 1. Applications of Scanning Probe Microscopy.- 2. Background: Scanning Tunneling Microscopy.- 3. Charge Density Waves in Pure Materials.- 4. Charge Density Wave Pinning.- 5.New Directions: CDWs in Nanocrystals.- 6. Concluding Remarks.- References.- Index of Subjects.
