Topological physics and strong electron–electron correlations in quantum materials are typically studied independently. However, there have been rapid recent developments in quantum materials in which topological phase transitions emerge when the single-particle band structure is modified by strong interactions. Here we demonstrate that the room-temperature phase of (TaSe₄)₂I is a Weyl semimetal with 24 pairs of Weyl nodes. Owing to its quasi-one-dimensional structure, (TaSe₄)₂I also hosts an established charge-density wave instability just below room temperature. We show that the charge-density wave in (TaSe₄)₂I couples the bulk Weyl points and opens a bandgap. The correlation-driven topological phase transition in (TaSe₄)₂I provides a route towards observing condensed-matter realizations of axion electrodynamics in the gapped regime, topological chiral response effects in the semimetallic phase, and represents an avenue for exploring the interplay of correlations and topology in a solid-state material.

量子材料中的拓扑物理和强电子-电子相关性通常是独立研究的。然而，量子材料最近取得了快速的发展，其中当单粒子带结构被强相互作用改变时，拓扑相变出现。_{在这里，我们证明(TaSe 4} ) ₂ I的室温相是具有24 对Weyl 节点的Weyl 半金属。由于其准一维结构，(TaSe ₄ ) ₂ I 在室温以下也具有确定的电荷密度波不稳定性。我们证明了 (TaSe ₄ ) _{2中的电荷密度波}我耦合了大块外尔点并打开了一个带隙。_{(TaSe 4} ) ₂ I中的相关驱动拓扑相变提供了一条途径来观察间隙状态下轴子电动力学的凝聚态实现、半金属相中的拓扑手性响应效应，并代表了探索相关性相互作用的途径和固态材料中的拓扑结构。