The dynamical axion field is a new state of quantum matter where the magnetoelectric response couples strongly to its low-energy magnetic fluctuations. It is fundamentally different from an axion insulator with a static quantized magnetoelectric response. The dynamical axion field exhibits many exotic phenomena such as axionic polariton and axion instability. However, these effects have not been experimentally confirmed due to the lack of proper topological magnetic materials. Here by combining analytic models and first-principles calculations, we predict a series of van der Waal layered Mn$_2$Bi$_2$Te$_5$-related topological antiferromagnetic materials could host the long-sought dynamical axion field with a topological origin. We also show a large dynamical axion field can be achieved in antiferromagnetic insulating states close to the topological phase transition. We further propose the optical and transport experiments to detect such a dynamical axion field. Our results could directly aid and facilitate the search for topological-origin large dynamical axion field in realistic materials.

中文翻译：

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拓扑反铁磁绝缘体Mn2Bi2Te5中的大动态轴子场

动态轴子场是量子物质的一种新状态，其中磁电响应与其低能磁涨落强烈耦合。它与具有静态量子化磁电响应的轴子绝缘体有着根本的不同。动态轴子场表现出许多奇异现象，例如轴子极化和轴子不稳定性。然而，由于缺乏合适的拓扑磁性材料，这些影响尚未通过实验得到证实。在这里，通过结合解析模型和第一性原理计算，我们预测了一系列范德瓦尔层状 Mn$_2$Bi$_2$Te$_5$ 相关的拓扑反铁磁材料可以承载长期寻找的具有拓扑起源的动力学轴子场. 我们还展示了在接近拓扑相变的反铁磁绝缘状态中可以实现大的动态轴子场。我们进一步提出了光学和传输实验来检测这种动态轴子场。我们的结果可以直接帮助和促进在现实材料中寻找拓扑起源的大型动态轴子场。