Magnetic topological quantum materials (TQMs) provide a fertile ground for the emergence of fascinating topological magneto-electric effects. Recently, the discovery of intrinsic antiferromagnetic (AFM) topological insulator MnBi₂Te₄ that could realize quantized anomalous Hall effect and axion insulator phase ignited intensive study on this family of TQM compounds. Here, we investigated the AFM compound MnBi₄Te₇ where Bi₂Te₃ and MnBi₂Te₄ layers alternate to form a superlattice. Using spatial- and angle-resolved photoemission spectroscopy, we identified ubiquitous (albeit termination dependent) topological electronic structures from both Bi₂Te₃ and MnBi₂Te₄ terminations. Unexpectedly, while the bulk bands show strong temperature dependence correlated with the AFM transition, the topological surface states with a diminishing gap show negligible temperature dependence across the AFM transition. Together with the results of its sister compound MnBi₂Te₄, we illustrate important aspects of electronic structures and the effect of magnetic ordering in this family of magnetic TQMs.

磁性拓扑量子材料 (TQM) 为迷人的拓扑磁电效应的出现提供了肥沃的土壤。最近，本征反铁磁 (AFM) 拓扑绝缘体 MnBi ₂ Te ₄的发现可以实现量化的反常霍尔效应和轴子绝缘体相，引发了对这一系列 TQM 化合物的深入研究。在这里，我们研究了 AFM 化合物 MnBi ₄ Te ₇，其中 Bi ₂ Te ₃和 MnBi ₂ Te ₄层交替形成超晶格。使用空间和角度分辨光电子能谱，我们从 Bi ₂ Te ₃和 MnBi ₂ Te ₄终端中识别出普遍存在的（虽然终端依赖）拓扑电子结构。出乎意料的是，虽然体带显示出与 AFM 跃迁相关的强烈温度依赖性，但间隙逐渐减小的拓扑表面状态在整个 AFM 跃迁中显示出可忽略的温度依赖性。连同其姐妹化合物 MnBi ₂ Te ₄的结果，我们说明了电子结构的重要方面以及该系列磁性 TQM 中磁性排序的影响。