Zinc-blende CaP, CaAs and CaSb as half-metals: A new route to magnetism in calcium compounds

TL;DR

This study theoretically predicts ferromagnetism and half-metallicity in zinc-blende calcium compounds like CaP, CaAs, and CaSb, which are stable and exhibit magnetism without transition metals, offering a new route to magnetic materials.

Contribution

First-principles calculations reveal ferromagnetism and half-metallicity in calcium compounds with zinc-blende structure, a novel approach without transition metals.

Findings

Calcium phosphide, arsenide, and antimonide are half-metals in zinc-blende structure.

Magnetism originates from p-orbitals of P, As, Sb and d-orbitals of calcium.

Ferromagnetism persists in (In$_{1-x}$Ca$_x$)Sb for doping rates x > 0.8.

Abstract

Existence of ferromagnetism in bulk calcium compounds is discovered theoretically. First-principles calculations of calcium phosphide, calcium arsenide and calcium antimonide in the zinc-blende structure have been performed to show the half-metallic ground state in each optimized stable structure. Magnetism comes from spin-polarization of electrons in $p$-orbitals of P, As or Sb and $d$-orbitals of calcium atoms. The half-metallicity is analogous to the half-metallic zinc-blende compounds, {\it e.g.} CrAs or CrSb, but the predicted compounds become ferromagnetic without transition metals. In (In$_{1-x}$Ca$_x$)Sb, the magnetism remains to be stable in a range of the doping rate ($x>0.8$).