Imaging the nanoscale phase separation in vanadium dioxide thin films at terahertz frequencies

Abstract

We use apertureless scattering near-field optical microscopy (SNOM) to investigate the nanoscale optical response of vanadium dioxide (VO2) thin films through a temperature-induced insulator-to-metal transition (IMT). We compare images of the transition at both mid-infrared (MIR) and terahertz (THz) frequencies, using a custom-built broadband THz-SNOM compatible with both cryogenic and elevated temperatures. We observe that the character of spatial inhomogeneities in the VO2 film strongly depends on the probing frequency. In addition, we find that individual insulating (or metallic) domains have a temperature-dependent optical response, 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.

References in corpus (20)

• Complexity in Strongly Correlated Electronic Systems
• Mott transition in VO2 revealed by infrared spectroscopy and nano-imaging
• Electrodynamics of Correlated Electron Materials
• Dynamical singlets and correlation-assisted Peierls transition in VO2
• Evidence for a Structurally-driven Insulator-to-metal Transition in VO2: a View from the Ultrafast Timescale
• Monoclinic and Correlated Metal Phase in VO_2 as Evidence of the Mott Transition: Coherent Phonon Analysis
• Evidence of a pressure-induced metallization process in monoclinic VO${}_2$
• Infrared spectroscopy and nano-imaging of the insulator-to-metal transition in vanadium dioxide
• Model for quantitative tip-enhanced spectroscopy and the extraction of nanoscale-resolved optical constants
• Correlated metallic state of vanadium dioxide
• Transfer of Spectral Weight in Spectroscopies of Correlated Electron Systems
• Landau Theory of the Finite Temperature Mott Transition
• Universal Aspects of Coulomb Frustrated Phase Separation
• Direct Observation of Decoupled Structural and Electronic Transitions and an Ambient Pressure Monoclinic-Like Metallic Phase of VO${}_2$
• Effective band-structure in the insulating phase versus strong dynamical correlations in metallic VO2
• Sequential Electronic and Structural Transitions in VO2 Observed Using X-ray Absorption Spectromicroscopy
• Resolving the VO${}_2$ controversy: Mott mechanism dominates the insulator-to-metal transition
• The RKKY interactions and the Mott Transition
• Ultrafast Electron-Lattice Coupling Dynamics in VO2 and V2O3 Thin Films
• Multiple crossovers and coherent states in a Mott-Peierls insulator

Cited by in corpus (17)

• Probes for Ultrasensitive THz Nanoscopy
• THz Near-Field Imaging of Extreme Subwavelength Metal Structures
• Reconfigurable Multistate Optical Systems Enabled by VO2 Phase Transitions
• Quantifying nanoscale electromagnetic fields in near-field microscopy by Fourier demodulation analysis
• Molecular Quantum Materials: Electronic Phases and Charge Dynamics in Two-Dimensional Organic Solids
• Cryogenic Magneto-Terahertz Scanning Near-field Optical Microscope (cm-SNOM)
• A 2D van der Waals Material for Terahertz Emission with Giant Optical Rectification
• Near-Field Terahertz Nanoscopy of Coplanar Microwave Resonators
• Visualizing heterogeneous dipole fields by terahertz light coupling in individual nano-junctions used in transmon qubits
• Nonequilibrium dynamics of superconductivity in the attractive Hubbard model
• Revealing subterahertz atomic vibrations in quantum paraelectrics by surface-sensitive spintronic terahertz spectroscopy
• Reconfigurable radiofrequency electronic functions designed with 3D Smith Charts in Metal-Insulator-Transition Materials
• Terahertz measurements on subwavelength-size samples down to the tunneling limit
• Ramp reversal memory in bulk crystals of 1T-TaS2
• Revealing domain wall stability during ultrafast demagnetization
• Enhanced coherent terahertz emission from critical superconducting fluctuations in YBa${}_2$Cu${}_3$O${}_{6.6}$
• Milliwatt average power, MHz-repetition rate, broadband THz generation in organic crystal BNA with diamond substrate