Collective Dynamics and Mesoscale Physics of Quasi-One-Dimensional Conductors

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This individual investigator award will fund a project to study moving charge-density waves (CDWs) in niobium triselenide films and single crystals. The project will combine crystal and film growth with various characterization techniques. The materials will be explored through the application of spatially and temporally resolved transport measurements as well as novel diffraction tools. In particular, spatially-resolved transport and coherent x-ray diffraction measurements will explore the cause of a recently discovered form of extremely slow creep-like collective motion that exhibits temporal order. A related first-order dynamic transition will also be studied. Spatially-resolved measurements of CDW conduction noise will be used to investigate spatio-temporal correlations in CDW dynamics. Through growth chamber and target modifications and lattice-matched substrates fully oriented films with improved grain sizes and transport properties will be grown. These films as well as single crystals will be used to fabricate a variety of CDW microstructures and heterostructures that will allow study of fundamental aspects of CDW physics, of interactions between the CDW, superconducting, and metallic states, and of potential applications of these remarkable materials. This work will provide excellent training to graduate and undergraduate students in the concepts and techniques of modern materials science, solid-state physics, and nanotechnology.Novel electronic materials including high-temperature superconductors, conducting polymers, carbon nanotubes, and charge-density-wave (CDW) conductors illuminate the fundamental physical processes that underlie how solid state electronic devices work, and provide opportunities for creating the electronics of tomorrow. Next to superconductors, CDW conductors are perhaps the most remarkable electronic materials ever discovered. An important barrier to the understanding, and practical application, of these materials has been the lack of high-quality thin films from which to fabricate devices. This barrier is now being overcome, and the first thin films of the CDW conductor niobium triselenide have been prepared. This individual investigator award will fund a project that focuses on improving the quality of these films, preparing unusual device structures from them, and then exploring the fundamental and useful properties of these devices. This work will provide excellent training to graduate and undergraduate students in the concepts and techniques of modern materials science, solid-state physics, and nanotechnology.