Comparison of Ab initio Low-Energy Models for LaFePO, LaFeAsO, BaFe2As2, LiFeAs, FeSe and FeTe: Electron Correlation and Covalency

TL;DR

This paper compares low-energy models for various iron-based superconductors derived from first-principles calculations, highlighting how covalency variations influence model parameters across different families.

Contribution

It provides a systematic comparison of effective Hamiltonians for multiple iron-based superconductors, emphasizing the role of covalency in parameter variation.

Findings

Model parameters vary systematically across different superconductor families.

Covalency between Fe-3d and pnictogen-/chalcogen-p orbitals explains parameter differences.

First-principles derived models reveal family-dependent electronic interactions.

Abstract

Effective low-energy Hamiltonians for several different families of iron-based superconductors are compared after deriving them from the downfolding scheme based on first-principles calculations. Systematic dependences of the derived model parameters on the families are elucidated, many of which are understood from the systematic variation of the covalency between Fe-3d and pnictogen-/chalcogen-p orbitals.