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Phase Transitions in Strongly Correlated Material, VO2, Investigated with Ultrafast Electron Diffraction

Event Details

Event Dates: 

Wednesday, March 5, 2014 - 3:00pm

Seminar Location: 

  • JILA X317

Speaker Name(s): 

Zhensheng Tao

Speaker Affiliation(s): 

Michigan State University
Seminar Type/Subject

Scientific Seminar Type: 

  • JILA Public Seminar

Event Details & Abstract: 

The phase transition in strongly correlated material, vanadium dioxide (VO2), is a highly interesting phenomenon. It is not only because of its promising application on the ultrafast electronic and photonic devices, but also due to the fundamental physics question it raised regarding to the complex interplay between correlated electrons with phonons and other degrees of freedom. Here, using optical reflectivity, TEM and ultrafast electron diffraction (UED), we investigated photo-induced phase transitions in VO2. We provide the evidences for 1) VO2 is a complex Mott insulator; 2) photo-induced phase transitions in

VO2 is a non-equilibrium charge-density driven process, which implies the importance of electron-electron strong correlation for its phase transition.

At the end, the new development of RF-compression ultrafast electron microscope at MSU will be introduced.