Inducing Fe moment in LaFeSi with p-block element substitution

We studied the LaFeSi phase using density functional theory based full-potential linearized augmented plane wave (FP-LAPW) method. Specifically we examined the effect of p-element substitution on the stability and magnetic properties focusing on pathways to induce Fe magnetic moments. We demonstrate that either partial or complete substitutions at the Si 2c-site by several p-block elements lead to non-zero Fe moments. Our theoretical study shows that partially substituted LaFeSi1-yGay and LaFeSi1-yAly are more thermodynamically stable than the fully substituted LaFeGa and LaFeAl. We also found that the P substitutions, either partial or complete, have the most negative formation energies, however the compounds containing phosphorus are non-magnetic. Our work highlights a pathway toward manipulations of the otherwise quenched Fe-moments in LaFeSi-related compounds and help in advancing the potential magnetic functionalities of LaFeX compounds. (C) 2022 Author(s)

Automated summary

We studied the LaFeSi phase using density functional theory and investigated the effect of p-element substitution on its stability and magnetic properties. We found that partial or complete substitutions at the Si 2c-site with p-block elements result in non-zero Fe moments. The partially substituted LaFeSi1-yGay and LaFeSi1-yAly were thermodynamically more stable than the fully substituted LaFeGa and LaFeAl. However, compounds containing phosphorus had the most negative formation energies but were non-magnetic. This work provides insights into manipulating the suppressed Fe-moments in LaFeSi-related compounds and advancing the magnetic functionalities of LaFeX compounds.