Topotactic Growth of Zintl Phase Eu₅In₂As₆ Nanowires with Antiferromagnetic Behavior

We demonstrate a topotactic transformation of zincblende InAs(Sb) nanowires into the Zintl phase Eu₅In₂As₆ through a vapor-solid mutual exchange process involving Eu and In in molecular beam epitaxy. This conversion preserves the polyhedral coordination lattice of the parent InAs(Sb) structure while inducing orthorhombic symmetry in the product phase, Eu₅In₂As₆, of which quasi-one-dimensional [InAs₃]^6- chains with tetrahedral sites align along the ⟨110⟩ direction of zincblende structure. Local and global magnetic characterization identified two distinct antiferromagnetic phase transitions at approximately 7 and 16 K in Eu₅In₂As₆ nanowires, potentially classified as altermagnetic phases. The versatility of the topotactic conversion of III-V semiconductor nanowires provides a platform for designing functional Zintl materials with tunable magnetic properties, making them promising candidates for spintronic applications.