Half-metallic antiferromagnetism in the ordered Cr1 − xCaxSb alloy from first-principles calculations

► We predict that Cr0.25Ca0.75Sb is a half-metallic (HM) antiferromagnet. ► The HM antiferromagnetism is robust against the lattice compression and expansion. ► The LDA+U scheme does not destroy the HM antiferromagnetism. ► The calculated formation energy indicates Cr0.25Ca0.75Sb is stable.