Ultrafast X-ray imaging of the light-induced phase transition in VO2

Abstract

Using light to control transient phases in quantum materials is an emerging route to engineer new properties and functionality, with both thermal and non-thermal phases observed out of equilibrium. Transient phases are expected to be heterogeneous, either through photo-generated domain growth or by generating topological defects, and this impacts the dynamics of the system. However, this nanoscale heterogeneity has not been directly observed. Here we use time- and spectrally resolved coherent X-ray imaging to track the prototypical light induced insulator-to-metal phase transition in vanadium dioxide on the nanoscale with femtosecond time resolution. We show that the early-time dynamics are independent of the initial spatial heterogeneity and observe a 200 fs switch to the metallic phase. A heterogeneous response emerges only after hundreds of picoseconds. Through spectroscopic imaging, we reveal that the transient metallic phase is a highly orthorhombically strained rutile metallic phase, an interpretation that is in contrast to those based on spatially averaged probes. Our results demonstrate the critical importance of spatially and spectrally resolved measurements for understanding and interpreting the transient phases of quantum materials.

References in corpus (7)

• Nonthermal pathways to ultrafast control in quantum materials
• Orbital-assisted metal-insulator transition in VO${}_2$
• Ultrafast nano-imaging of the order parameter in a structural phase transition
• Universal phase dynamics in VO2 switches revealed by ultrafast operando diffraction
• Phase Fluctuations and the Absence of Topological Defects in Photo-excited Charge Ordered Nickelate
• Time-resolved resonant elastic soft X-ray scattering at Pohang Accelerator Laboratory X-ray Free Electron Laser
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Cited by in corpus (17)

• Transient dynamics of the phase transition in VO2 revealed by mega electron-volt ultrafast electron diffraction
• Strong laser physics, non-classical light states and quantum information science
• Photo-induced nonequilibrium states in Mott insulators
• Coexisting phases of individual VO${}_2$ nanoparticles for multilevel nanoscale memory
• Picosecond volume expansion drives a later-time insulator-metal transition in a nano-textured Mott Insulator
• Relativistic ultrafast electron diffraction at high repetition rates
• Imaging ferroelectric domains with soft X-ray ptychography at the oxygen K-edge
• Molecular orbital formation and metastable short-range ordered structure in VO${}_2$
• Tunable Spatiotemporal Orders in Driven Insulators
• Small polarons mediated near-room-temperature metal-insulator transition in vanadium dioxide and their hopping dynamics
• Evidence for bootstrap percolation dynamics in a photo-induced phase transition
• Switching of an antiferromagnet controlled by spin canting in a laser-induced hidden phase
• Ultrafast spatiotemporal dynamics of a charge-density wave using femtosecond dark-field momentum microscopy
• Dislocation-Driven Nucleation Type Switching Across Repeated Ultrafast Magnetostructural Phase Transition
• Correlative Ultrafast Imaging of a Propagating Photo-Driven Phase Transition Using 4D STEM
• Tuning of Localized Surface Plasmons in Vanadium Dioxide Nanoparticles via Size and Insulator-Metal Transition
• Current-induced successive structural phase transitions beyond thermal equilibrium in single-crystal VO2