Real time cumulant approach for charge transfer satellites in x-ray photoemission spectra

TL;DR

This paper introduces a real-time, real-space cumulant approach combined with time-dependent density functional theory to accurately calculate charge-transfer satellites in X-ray photoemission spectra of correlated materials, aligning well with experimental data.

Contribution

The paper presents a novel first-principles method for calculating charge-transfer satellites in X-ray spectra using a real-time cumulant approach and TDDFT, addressing previous computational challenges.

Findings

Good agreement with experimental spectra for TiO₂ and NiO.

Provides a physical interpretation of charge-transfer satellites as transient responses.

Demonstrates effectiveness of the method for correlated materials.

Abstract

X-ray photoemission spectra generally exhibit satellite features in addition to the quasi-particle peaks due to many-body excitations, which have been of considerable theoretical and experimental interest. However, the satellites attributed to charge-transfer (CT) excitations in correlated materials have proved difficult to calculate from first principles. Here we report a real-time, real-space approach for such calculations based on a cumulant representation of the core-hole Green's function and time-dependent density functional theory. This approach also yields an interpretation of CT satellites in terms of a complex oscillatory, transient response to a suddenly created core hole. Illustrative results for TiO$_2$ and NiO are in good agreement with experiment.