Microscopic theory of resonant soft x-ray scattering in systems with charge order

TL;DR

This paper develops a microscopic theory for resonant soft x-ray scattering in systems with charge order, incorporating realistic band structures and many-body effects, to better understand experimental observations in cuprates.

Contribution

It introduces a functional determinant method that models RSXS with realistic band structures, including excitonic effects and the orthogonality catastrophe, advancing theoretical understanding.

Findings

Two-peak structure explained by dynamic nesting in cuprate band structure

Evidence for well-defined high-energy quasiparticles in charge-ordered systems

Agreement with RSXS measurements in stripe-ordered LBCO

Abstract

We present a microscopic theory of resonant soft x-ray scattering (RSXS) that accounts for the delocalized character of valence electrons. Unlike past approaches defined in terms of form factors for atoms or clusters, we develop a functional determinant method that allows us to treat realistic band structures. This method builds upon earlier theoretical work in mesoscopic physics and accounts for both excitonic effects as well as the orthogonality catastrophe arising from interaction between the core hole and the valence band electrons. Comparing to RSXS measurements from stripe-ordered LBCO, we show that the two-peak structure observed near the O K edge can be understood as arising from dynamic nesting within the canonical cuprate band structure. Our results provide evidence for reasonably well-defined, high-energy quasiparticles