Nanoscale-femtosecond dielectric response of Mott insulators captured by two-color near-field ultrafast electron microscopy
Abstract
Characterizing and controlling the out-of-equilibrium state of nanostructured Mott insulators hold great promises for emerging quantum technologies while providing an exciting playground for investigating fundamental physics of strongly-correlated systems. Here, we use two-color near-field ultrafast electron microscopy to photo-induce the insulator-to-metal transition in a single VO2 nanowire and probe the ensuing electronic dynamics with combined nanometer-femtosecond resolution (10−21 m ∙ s). We take advantage of a femtosecond temporal gating of the electron pulse mediated by an infrared laser pulse, and exploit the sensitivity of inelastic electron-light scattering to changes in the material dielectric function. By spatially mapping the near-field dynamics of an individual nanowire of VO2, we observe that ultrafast photo-doping drives the system into a metallic state on a timescale of ~150 fs without yet perturbing the crystalline lattice. Due to the high versatility and sensitivity of the electron probe, our method would allow capturing the electronic dynamics of a wide range of nanoscale materials with ultimate spatiotemporal resolution.
- Publication:
-
Nature Communications
- Pub Date:
- 2020
- DOI:
- 10.1038/s41467-020-19636-6
- arXiv:
- arXiv:2006.02641
- Bibcode:
- 2020NatCo..11.5770F
- Keywords:
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- Physics - Applied Physics;
- Condensed Matter - Materials Science
- E-Print:
- 32 pages, 4 figures