Electron energy-loss spectroscopy: A versatile tool for the investigations of plasmonic excitations

Highlights: • High energy (∼85 meV) and momentum (∼0.03 Å⁻¹) resolution in electron energy-loss spectroscopy allow for the observation of fine details in the dispersion collective excitations. • Low temperature measurements in electron energy-loss spectroscopy technology lead to new insights into the electronic structure of topical materials. • We demonstrate that the plasmon dispersion allows insight into the interplay of the conduction electrons with other degrees of freedom. - Abstract: The inelastic scattering of electrons is one route to study the vibrational and electronic properties of materials. Such experiments, also called electron energy-loss spectroscopy, are particularly useful for the investigation of the collective excitations in metals, the charge carrier plasmons. These plasmons are characterized by a specific dispersion (energy–momentum relationship), which contains information on the sometimes complex nature of the conduction electrons in topical materials. In this review we highlight the improvements of the electron energy-loss spectrometer in the last years, summarize current possibilities with this technique, and give examples where the investigation of the plasmon dispersion allows insight into the interplay of the conduction electrons with other degrees of freedom