Plasmonic Properties of SrVO_3 Bulk and Nanostructures

摘要

Correlated metals, such as SrVO_3 (SVO) or SrNbO_3, are promising materialsfor optical devices such as transparent conductors. Here, a real-space andreciprocal-space electron-energy-loss-spectroscopy (EELS) investigation of SVObulk and nanostructures is reported. An intense 1.35 eV excitation with a weakenergy dispersion is observed in the loss function and is attributed to a bulkplasmonic excitation from the 3d-t_(2g) orbitals. Ab initio calculations done withina time-dependent density functional theory framework reveal that a 1.5 bandrenormalization is sufficient to reproduce quantitatively this d–d plasmonenergy and dispersion. The corresponding localized surface plasmon (LSP)peaks are measured by EELS on various nanostructures and are compared tofinite-difference time-domain simulations. These LSPs exhibit quality factorsabove canonical materials (e.g., indium tin oxide) in the near-infrared regime,demonstrating that SVO is also a material of high interest for plasmonic applications.Finally, by phasing out the surface plasmon contribution with EELScollected at minute off-dipolar conditions, the bulk-type plasmonic values areretrieved with nanometrical resolution. Core–shelled electronic structures arethen observed for nanorods designed by focused ion beam (FIB), revealing abandgap opening due to FIB damage. It is envisioned that similar bulk measurementcan be feasible for most of the transition metal oxide nanostructures.