Bands, resonances, edge singularities and excitons in core level spectroscopy investigated within the dynamical mean-field theory

¹ Max Planck Institute for Solid State Research - Heisenbergstraße 1, 70569 Stuttgart, Germany
² Department of Physics and Astronomy, University of British Columbia - Vancouver, British Columbia V6T1Z1, Canada
³ Max Planck Institute for Chemical Physics of Solids - Nöthnitzerstraße 40, 01187 Dresden, Germany
⁴ Institut für Theoretische Physik und Astrophysik, Universität Würzburg - Am Hubland, D-97074 Würzburg, Germany
⁵ Centre de Physique Théorique, CNRS, École Polytechnique - 91128 Palaiseau, France
⁶ Institut für Festkörperphysik, Technische Universität Wien - 1040 Vienna, Austria

Received: 23 September 2014
Accepted: 20 November 2014

Abstract

Using a recently developed impurity solver we exemplify how dynamical mean-field theory captures band excitations, resonances, edge singularities and excitons in core level x-ray absorption spectroscopy (XAS) and core level photo electron spectroscopy (cPES) on metals, correlated metals and Mott insulators. Comparing XAS at different values of the core-valence interaction shows how the quasiparticle peak in the absence of core-valence interactions evolves into a resonance of similar shape, but different origin. Whereas XAS is rather insensitive to the metal insulator transition, cPES can be used, due to nonlocal screening, to measure the amount of local charge fluctuation.