Due to quasi-one-dimensional confinement, nanowires possess unique electronic properties, which can promote specific device architectures. However, nanowire growth presents paramount challenges, limiting the accessible crystal structures and elemental compositions. Here we demonstrate solid-state topotactic exchange that converts wurtzite InAs nanowires into Zintl Eu₃In₂As₄. Molecular-beam-epitaxy-based in situ evaporation of Eu and As onto InAs nanowires results in the mutual exchange of Eu from the shell and In from the core. Therefore, a single-phase Eu₃In₂As₄ shell grows, which gradually consumes the InAs core. The mutual exchange is supported by the substructure of the As matrix, which is similar across the wurtzite InAs and Zintl Eu₃In₂As₄ and therefore is topotactic. The Eu₃In₂As₄ nanowires undergo an antiferromagnetic transition at a Néel temperature of ~6.5 K. Ab initio calculations confirm the antiferromagnetic ground state and classify Eu₃In₂As₄ as a C₂T axion insulator, hosting both chiral hinge modes and unpinned Dirac surface states. The topotactic mutual-exchange nanowire growth will, thus, enable the exploration of intricate magneto-topological states in Eu₃In₂As₄ and potentially in other exotic compounds.

由于准一维限制，纳米线具有独特的电子特性，可以促进特定的器件架构。然而，纳米线的生长面临着巨大的挑战，限制了可获得的晶体结构和元素组成。在这里，我们演示了固态拓扑交换，将纤锌矿 InAs 纳米线转化为 Zintl Eu ₃ In ₂ As ₄ 。基于分子束外延的 Eu 和 As 原位蒸发到 InAs 纳米线上，导致壳中的 Eu 和核中的 In 相互交换。因此，单相Eu ₃ In ₂ As ₄壳生长，逐渐消耗InAs核。这种相互交换由 As 基质的子结构支持，这在纤锌矿 InAs 和 Zintl Eu ₃ In ₂ As ₄中是相似的，因此是拓扑的。 Eu ₃ In ₂ As ₄纳米线在〜6.5 K的尼尔温度下经历反铁磁转变。从头算计算证实了反铁磁基态并将Eu ₃ In ₂ As ₄分类为C ₂ T轴子绝缘体，具有两种手性铰链模式和未固定的狄拉克表面状态。因此，拓扑互交换纳米线生长将使得能够探索Eu ₃ In ₂ As ₄中复杂的磁拓扑态以及其他潜在化合物中的复杂磁拓扑态。