2017/11/14 by H. T. Stinson, A. Sternbach, O. Najera +8 · 134 citations
Engineering · Materials Science · Physics and Astronomy · #Dimer #Microscopy #Nanoscopic scale #Phase transition #Plasmonic and Surface Plasmon Research #Scattering #Terahertz radiation #Thermal Radiation and Cooling Technologies #Thin film #Transition Metal Oxide Nanomaterials #Vanadium dioxide #cond-mat.mes-hall #cond-mat.str-el #physics.ins-det #physics.optics
paper · pdf · doi:10.1038/s41467-018-05998-5
published in Nature Communications 9(1), 3604 (Nature Portfolio)
arxiv created 2017/11/14 · openalex created_date 2017/12/04 · openalex publication_date 2018/08/31 · arxiv updated 2018/10/24 · openalex updated_date 2026/08/06
Abstract Vanadium dioxide (VO 2 ) 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 VO 2 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 VO 2 , which account for a continuous temperature dependence of the optical response of the VO 2 in the insulating state.