Speaker: Richard Haglund, Vanderbilt University
Date & Time: October 14, 2008 - 1:30pm
Location: Serin 385
Exploring the Metal-Insulator Transition in VO2 Nanoparticles
Physics and Astronomy
Richard Haglund, Vanderbilt University
1:30 PM, Serin 385
The semiconductor-to-metal transition (SMT) in vanadium dioxide, influenced by both strong electron correlation and lattice instability, can be induced either by adiabatic heating and cooling, or by laser-induced photodoping at femtosecond time scales. We are studying the effects of size on the structural phase transition by fabricating and measuring the optical response of both single VO2 nanoparticles and nanoparticle arrays; our motivation is to understand the specific nature of the defects that lead to heterogeneous nucleation of the SMT. After reviewing some relevant background from experiments by us and others, I will concentrate on recent results from Raman spectroscopy of single VO2 nanoparticles and surface-enhanced Raman spectroscopy on VO2 nanoparticle arrays. This last is an example of a larger effort in our group to use the SMT in VO2 to alter the plasmonic response of composite VO2-metal nanostructures.
*In collaboration with Eugene Donev, Leonard Feldman, René Lopez and Jed Ziegler. Research supported by the National Science Foundation and the Office of Science, U. S. Department of Energy.
Host: Leonard Feldman