Plasmonic Properties of SrVO3 Bulk and Nanostructures

Abstract

Correlated metals, such as SrVO3 (SVO) or SrNbO3, are promising materials for optical devices such as transparent conductors. Here, a real-space and reciprocal-space electron-energy-loss-spectroscopy (EELS) investigation of SVO bulk and nanostructures is reported. An intense 1.35 eV excitation with a weak energy dispersion is observed in the loss function and is attributed to a bulk plasmonic excitation from the 3d-t2g orbitals. Ab initio calculations done within a time-dependent density functional theory framework reveal that a 1.5 band renormalization is sufficient to reproduce quantitatively this d–d plasmon energy and dispersion. The corresponding localized surface plasmon (LSP) peaks are measured by EELS on various nanostructures and are compared to finite-difference time-domain simulations. These LSPs exhibit quality factors above 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 EELS collected at minute off-dipolar conditions, the bulk-type plasmonic values are retrieved with nanometrical resolution. Core–shelled electronic structures are then observed for nanorods designed by focused ion beam (FIB), revealing a bandgap opening due to FIB damage. It is envisioned that similar bulk measurement can be feasible for most of the transition metal oxide nanostructures.