# $d^0$ half-metallic ferromagnetism in CaN and CaAs pnictides: An ab initio study

## TL;DR

This study uses density functional theory to predict that certain CaN and CaAs compounds in specific structures are ferromagnetic half-metals with potential for spintronics, based on their electronic structure and magnetic properties.

## Contribution

It is the first ab initio investigation demonstrating ferromagnetism in CaN and CaAs in specific structural phases, highlighting their potential as spintronic materials.

## Key findings

- CaN in cubic, NiAs, and WZ structures is ferromagnetic with 1μB magnetic moment.
- CaAs in zincblende structure exhibits ferromagnetism with 1μB magnetic moment.
- Magnetism originates from anion p states and flat p bands at the Fermi level.

## Abstract

Conventional magnetism occurs in systems which contain transition metals or rare earth ions with partially filled $d$ or $f$ shells. It is theoretically predicted that compounds of groups IA and IIA with IV and V, in some structural phases, are ferromagnetic half-metals which made them new candidates for spintronics applications. Employing density functional theory (DFT) we investigate magnetism in binary compounds CaN and CaAs. Regarding the structure of analogous magnetic materials and experimental results of CaAs synthesis, we have considered two cubic structures: rocksalt (RS) and zincblende (ZB), and four hexagonal structures: NiAs, wurtzite (WZ), anti-NiAs, and NaO. The calculated results show that CaN in cubic, NiAs, and wurtzite structures, and CaAs only in zincblende phase have ferromagnetic ground states with a magnetic moment of $1\mu _B$. Electronic structure analysis of these materials indicates that magnetism originates from anion $p$ states. Existence of flat $p$ bands and consequently high density of states at the Fermi level of magnetic structures gives rise to Stoner spin splitting and spontaneous ferromagnetism.