Direct and inverse photoemission spectra from the screened multichannel Dyson equation

TL;DR

This paper introduces a screened multichannel Dyson equation that accurately models photoemission spectra by properly including screening effects, improving upon standard methods like GW, as demonstrated with silicon.

Contribution

The paper develops a new screened multichannel Dyson equation that correctly accounts for screening in particle interactions, enhancing spectral predictions over existing approaches.

Findings

Accurately captures silicon plasmon satellite position.

Standard approaches overestimate plasmon satellite binding energy.

Proper screening is crucial for reliable spectral simulations.

Abstract

We present the screened multichannel Dyson equation for the simulation of both direct and inverse photoemission spectra from first principles. The screened multichannel Dyson equation improves upon the standard multichannel Dyson equation by correctly including the screening of all particle-particle and electron-hole interactions due to the presence of the other electrons. Using the example of bulk silicon, we demonstrate that the screened multichannel Dyson equation can capture the main features of the direct and inverse photoemission spectra. In particular, it captures the correct position of the silicon plasmon satellite, unlike standard many-body approaches such as $GW$, which strongly overestimates the binding energy of this satellite. Finally, we show that also the standard multichannel Dyson equation and the second-Born approximation strongly overestimate the binding energy of the plasmon satellite, thus demonstrating the importance of properly screening all particle-particle and electron-hole interactions.