AVS 60th International Symposium and Exhibition
    Thin Film Thursday Sessions
       Session TF+AS+EM+NS+SS-ThM

Paper TF+AS+EM+NS+SS-ThM6
Bi-Chromatic Far-Field Optical Probing the Percolative Metal-Insulator Transition in VO2 Thin Film

Thursday, October 31, 2013, 9:40 am, Room 104 A

Session: Thin Film: Growth and Characterization I
Presenter: L. Wang, The College of William and Mary
Authors: L. Wang, The College of William and Mary
I. Novikova, The College of William and Mary
J.M. Klopf, Thomas Jefferson National Accelerator Facility
S. Madaras, Thomas Jefferson National Accelerator Facility
E. Madaras, NASA Langley Research Center
G.P. Williams, Thomas Jefferson National Accelerator Facility
R.A. Lukaszew, The College of William and Mary
Correspondent: Click to Email
Vanadium dioxide (VO2) is a prototype of a highly correlated electron material exhibiting a metal-insulator transition (MIT) that can be thermally, electrically or optically controlled. Using near field optical techniques it has recently been shown that the thermally induced MIT in VO2 thin films is initiated by nucleation of nanoscale metallic puddles in the insulating host. Here we exploit these microscopic changes in phase-composition at the onset and during the MIT on a VO2 thin film sample by observing their effect on the optical properties using far-field infrared (IR) and broadband coherent Terahertz (THz) light optical techniques. We model the transition and are able to accurately describe it particularly regarding the different temperatures recorded at the onset of the MIT depending on the probe used. Further, we compare the optical and DC transport responses, and our findings and modeling settle the question regarding the different transition temperatures observed in each case on the same sample under thermally induced MIT. Finally, we show that Mie scattering explains the observed wavelength scaling dependence of the optical response as function of temperature near the MIT.