New noncollinear antiferromagnet Mn3Al for antiferromagnetic spintronics

Hexagonal noncollinear antiferromagnets, such as Mn 3 Sn, Mn 3 Ge, and Mn 3 Ga, have garnered significant attention in recent years due to their potential for supplying large anisotropic anomalous and spin Hall conductance. In particular, noncollinear antiferromagnetic tunnel junctions have been fabricated, demonstrating their applications in antiferromagnetic spintronics in future. However, hexagonal Mn 3 Al, a noncollinear antiferromagnet that has non-heavy metal elements, has never been reported. In this study, we not only predict the noncollinear antiferromagnet Mn 3 Al through first-principles calculations and experimentally confirm the existence of hexagonal Mn 3 Al, but also predict the existence of large anomalous Hall conductance for Mn 3 Al. Our calculations reveal that Mn 3 Al can be utilized in antiferromagnetic tunnel junctions and possesses anisotropic anomalous Hall conductance. Our calculations show a large σ z x = 1398 (Ω⋅cm) − 1 above the Fermi level, which is caused by the Weyl points in momentum space for Mn 3 Al. σ z x could be raised from 99.7 (Ω⋅cm) − 1 for Mn 3 Al to 412 (Ω⋅cm) − 1 for Mn 3 Al 0.5 Si 0.5 at Fermi level by substituting the Al atoms with Si atoms. More Si content further raises the value of σ z x to a maximum 952 (Ω⋅cm) − 1 for Mn 3 Al 0.35 Si 0.65 within the rigid band approximation. Furthermore, the films grown on Si(111) substrates suggest compatibility with semiconductor devices, thus broadening the applications of Mn 3 Al and expanding the family of noncollinear antiferromagnets.