Plasmon excitations in infinite-layer nickelate superconductors

Recent resonant inelastic x-ray scattering (RIXS) studies have revealed low-energy plasmon excitations in both hole- and electron-doped cuprates, highlighting their relevance for the normal state and superconducting properties. Moreover, the plasmonic charge excitations in cuprates are well described by the t-J-V model with long-range Coulomb interaction, providing a new way to determine the charge dynamics and related electronic energy scales. Here, we propose to apply this sensitivity of RIXS to study the newly discovered infinite-layer nickelate superconductors. From the plasmon spectra we will determine the parameter set that describes the low-energy physics of the nickelates, which is so far missing. In this fashion, key questions including their similarities to the cuprates, especially the strength of electronic interactions can be addressed. Furthermore, by following the evolution of charge excitations as a function of Tc, their roles in superconductivity will be examined.