Imaging the nanoscale phase separation in vanadium dioxide thin films at terahertz frequencies
Abstract
Vanadium dioxide (VO2) is a material that undergoes an insulator–metal transition upon heating above 340 K. It remains debated as to whether this electronic transition is driven by a corresponding structural transition or by strong electron–electron correlations. Here, we use apertureless scattering near-field optical microscopy to compare nanoscale images of the transition in VO2 thin films acquired at both mid-infrared and terahertz frequencies, using a home-built terahertz near-field microscope. We observe a much more gradual transition when THz frequencies are utilized as a probe, in contrast to the assumptions of a classical first-order phase transition. We discuss these results in light of dynamical mean-field theory calculations of the dimer Hubbard model recently applied to VO2, which account for a continuous temperature dependence of the optical response of the VO2 in the insulating state.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 06, 2018
- Source ID
- 10.1038/s41467-018-05998-5
Entities
People
- A. S. McLeod
- A. Sternbach
- Amy Mueller
- D. N. Basov
- H. T. Kim
- H. T. Stinson
- Loic Anderegg
- M. Rozenberg
- O. Najera
- R. Jing
- Tetiana Slusar
Organizations
- Agence Nationale de la Recherche
- Army Research Office
- Gordon and Betty Moore Foundation
- Office of Naval Research