Quantitative comparison of LDA+DMFT and ARPES spectral functions

TL;DR

This paper presents a method for quantitatively comparing theoretical LDA+DMFT spectral functions with ARPES experimental data, emphasizing the importance of including experimental features for accurate analysis in iron-based high-temperature superconductors.

Contribution

It introduces a robust procedure to incorporate experimental effects into theoretical spectral functions for better comparison with ARPES data.

Findings

Theoretical spectral functions must include photoionization cross section effects.

Experimental energy and angular resolutions significantly impact spectral function comparison.

Accounting for photohole lifetime effects improves the match between theory and experiment.

Abstract

The emergence of angle-resolved photoemission spectroscopy (ARPES) made it possible to observe electronic dispersion directly as a spectral function map. On the other hand, a spectral function map can be obtained theoretically, for example, in the LDA+DMFT method. The electronic band on such a map is characterized not only by its energy position at a given $k$-point, but also by its width and intensity. To illustrate a way of quantitative comparison of theoretical spectral functions and ARPES data, spectral functions obtained by the LDA+DMFT method are chosen. It is shown that the theoretical spectral functions should take into account a number of experimental features: the photoionization cross section, the experimental energy and angular resolution, as well as the effects of the photohole lifetime arising in the process of photoemission. In this article, we present a robust procedure for taking these experimental features into account by the example of iron-based high-temperature superconductors (HTSC) systems: NaFeAs and FeSe on a SrTiO$_3$ substrate.