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，纳米线的生长带来了最大的挑战，限制了可接近的晶体结构和元素组成。在这里，我们展示了将纤锌矿 InAs 纳米线转化为 Zintl Eu₃In₂As₄ 的固态拓扑逆移交换。基于分子束外延的 Eu 和 As 原位蒸发到 InAs 纳米线上，导致 Eu 来自壳层和 In 来自核心的相互交换。因此，单相 Eu₃In₂As₄ 壳层生长，逐渐消耗 InAs 内核。相互交换由 As 矩阵的子结构支持，该子结构在纤锌矿 InAs 和 Zintl Eu₃In₂As₄ 中相似，因此是拓扑策略。Eu₃In₂As₄ 纳米线在 ~6.5 K 的 Néel 温度下发生反铁磁转变。从头计算确认了反铁磁基态，并将 Eu₃In₂As₄ 归类为 C₂T 轴子绝缘体，具有手性铰链模式和非固定的 Dirac 表面状态。因此，拓扑互交换纳米线的生长将能够探索 Eu₃In₂As₄ 中复杂的磁拓扑状态，并可能在其他奇异化合物中探索。