Characterization and manipulation of broken symmetry materials at phase boundaries

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The ability to control the electronic properties of strongly correlated electronic materials (materials that exhibit electronic structure that is dominated by the lattice nuclei) will include observation and manipulation of phase transitions. Low dimensional materials represent one class in which both charge density wave (CDW) and spin density wave (SDW) ground states can be observed. This project had two major goals: to observe the inelastic (magnon) scattering from low dimensional SDW materials and to characterize magnetic defects within a CDW lattice. Toward these ends, the authors developed the capability of monitoring Raman spectra for weak CDW materials and SDW materials in high magnetic fields and also used isotopic enrichment to characterize the spatial extent of spin density in some photo-irradiated CDW samples. No magnon signatures or field-induced phase transitions were observed. Detailed spatial and dynamics characteristics of photo-induced magnetic defects in CDW samples were obtained