Near-Field Nanoscopy of Metal-Insulator Phase Transitions Towards Synthesis of Novel Correlated Transition Metal Oxides and Their Interaction with Plasmon Resonances
Technical Report,01 Feb 2012,30 Sep 2015
California State University - Long Beach Long Beach United States
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The performed project was centered around two separate, albeit related topics. The high-resolution infrared near-field imaging experiments were performed to better understand the origin of emergence of metal insulator transitions MIT in known transition metal oxides and to utilize the phase transition states of VO2 to control and manipulate local plasmon resonaces. First, we imaged the charge dynamics in MITof both amorphous VO2 films and stress free suspended VO2 crystals and probed the existence of mixed phases in tapered suspended crystalVO2 beams. Then we studied the interaction of VO2 with plasmons. Both the film VO2 and the crystal VO2 were explored for local unprecedented control of local plasmon light concentrations. We have demonstrated for the first time dynamic reversible switching of VO2metal-insulator transition and control of plasmonic nanoantennas dipolar modes. The other component of the work was an exploratory synthesis of novel transition metal oxides and chalcogenides, which resulted in discovery of novel phases such as BaYFeO4, CaGaYO4, Li4MgOsO6, Li4NiOsO6, Li3Ni2OsO6, La3Si1-xAlxCuQ7 Q S, Se and Ca2ScOsO6. We successfully synthesized the single-phase samples of the above-mentioned phases and investigated their crystal structures and physical properties.