Comment on paper arXiv:17070526v1 "Electronic structure of FeSe monolayer superconductors: shallow bands and correlations" by Sadovskii group

TL;DR

This paper critiques two inaccuracies in a previous study on FeSe monolayer superconductors, clarifying the role of electron-phonon interactions and the explanation of ARPES replica bands, emphasizing the need for correct theoretical interpretations.

Contribution

It clarifies misconceptions in prior work by correcting the understanding of electron-phonon coupling and ARPES replica bands in FeSe monolayer superconductors.

Findings

The electron-phonon coupling constant used previously is irrelevant for superconductivity.

LDA+DMFT cannot explain ARPES replica bands in FeSe monolayers.

Previous conclusions about small EPI and replica bands are incorrect.

Abstract

We comment two incorrect statements given in Ref.1. (A) - In order to show that the electron-phonon interaction (EPI) is very small and irrelevant for superconductivity in 1UC FeSe/SrTiO3 system, the authors of Ref.1 use an EPI coupling constant which does not enter in any theory of superconductivity. So, their conclusion on the smallness of the EPI in 1UC FeSe/SrTiO3 is incorrect. Accordingly, their coupling constant has also nothing to do with the EPI coupling with the forward scattering peak (EPI-FSP), which is proposed recently in order to explain high Tc in 1UC FeSe/SrTiO3. (B) - In Ref.1 it is claimed that the experimentally resolved ARPES replica bands can be explained by the LDA+DMFT method. We show that this statement is also incorrect, i.e. the LDA+DMFT method in Ref.1 is unable to explain the replica bands.