Effects of magnetic dopants in (Li$_{0.8}$M$_{0.2}$OH)FeSe (M = Fe, Mn, Co): a density-functional theory study using band unfolding technique

TL;DR

This study uses density-functional theory and band unfolding to analyze how Fe, Mn, and Co dopants affect the electronic band structure of (Li$_{0.8}$M$_{0.2}$OH)FeSe, revealing doping-induced shifts and layer-dependent electronic differences.

Contribution

It provides a detailed first-principles analysis of dopant effects on band structures, highlighting the minimal impact of magnetic ordering and layer-specific electronic variations.

Findings

Fe doping shifts the Fermi level and alters band profiles.

Surface FeSe layers show distinct electronic features from inner layers.

Mn and Co doping produce similar band structure modifications.

Abstract

The effects of Fe dopants in (Li$_{0.8}$Fe$_{0.2}$OH)FeSe on the electronic band structure are investigated by band unfolding ($k$-projection) technique based on first-principles supercell calculations. Doping 20\% Fe into the LiOH layers has significant effects on the band structure, that is, the Fe impurities doping electrons to the FeSe layers not only shift the Fermi level, but also induce substantial changes in the profile of bands around the Fermi level. However, the magnetic ordering in the dopants has minor effects on the band structure due to the fact that there is only a weak bonding between the LiOH and FeSe layers. Electronic bands for the surface FeSe layer show noticeable differences from those for inner layers in both the location of the Fermi level and details of the bands near the high symmetry points. The band structure for the surface FeSe layer where the Fe atoms are in checkerboard antiferromagnetic order is consistent with angle-resolved photoemission spectroscopy results. Mn and Co have similar doping effects on the band structure of (LiOH)FeSe.