Topotactic Growth of Zintl Phase Eu${}_5$In${}_2$As${}_6$ Nanowires with Antiferromagnetic Behavior

We demonstrate a topotactic transformation of zincblende InAs(Sb) nanowires into the Zintl phase Eu${}_5$In${}_2$As${}_6$ 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, Eu${}_5$In${}_2$As${}_6$, in which quasi-one-dimensional [InAs${}_3$]${}^6$${}^{-}$ chains with tetrahedral sites align along the <110> direction of the zincblende structure. Local and global magnetic characterization identified two distinct antiferromagnetic phase transitions at approximately 7 K and 16 K in Eu${}_5$In${}_2$As${}_6$ 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.