Theory of RIXS in strongly correlated electron systems: Mott gap excitations in cuprates

TL;DR

This paper provides a theoretical analysis of RIXS spectra in cuprates, revealing how it can be used to study momentum-dependent charge excitations in strongly correlated electron systems.

Contribution

It introduces a theoretical framework for RIXS in cuprates using the Hubbard model and numerical diagonalization, aligning well with experimental data.

Findings

RIXS spectra show clear momentum dependence of Mott gap excitations.

Good agreement between theoretical calculations and experimental results.

RIXS is validated as a tool for studying charge excitations in strongly correlated systems.

Abstract

We theoretically examine the momentum dependence of resonant inelastic x-ray scattering (RIXS) spectrum for one-dimensional and two-dimensional cuprates based on the single-band Hubbard model with realistic parameter values. The spectrum is calculated by using the numerical diagonalization technique for finite-size clusters. We focus on excitations across the Mott gap and clarify spectral features coming from the excitations as well as the physics behind them. Good agreement between the theoretical and existing experimental results clearly demonstrates that the RIXS is a potential tool to study the momentum-dependent charge excitations in strongly correlated electron systems.