Band-gap and Slater-Pauling rule in half-metallic Ti2-based Heusler alloys: A first-principles study

► A half-metallic antiferromagnet, Ti2MnAl alloy with Hg2CuTi structure, was predicted. ► Ti2YAl (Y=Mn, Fe, Co, and Ni) alloys follow a new Slater-Pauling rule, Mt=Zt−18. ► Origin of the band-gap for Ti2YAl (Y=Mn, Fe, Co, and Ni) alloys was investigated.