High-temperature self-energy corrections to x-ray absorption spectra

TL;DR

This paper investigates how finite-temperature quasiparticle self-energy corrections affect x-ray absorption spectra, revealing temperature-induced broadening and shifts near plasmon excitation thresholds.

Contribution

It introduces a method to incorporate finite-temperature self-energy corrections into x-ray absorption spectra calculations using a polynomial parametrization within the GW approximation.

Findings

Temperature decreases electron lifetime, broadening spectra.

Quasiparticle shifts are significantly affected near plasmon onset.

Spectral features are sensitive to temperature variations.

Abstract

Effects of finite-temperature quasiparticle self-energy corrections to x-ray absorption spectra are investigated within the finite-temperature quasiparticle local density GW approximation up to temperatures $T$ of order the Fermi temperature. To facilitate the calculations, we parametrize the quasiparticle self-energy using low-order polynomial fits. We show that temperature-driven decrease in the electron lifetime substantially broadens the spectra in the near-edge region with increasing $T$. However, the quasiparticle shift is most strongly modified near the onset of plasmon excitations.