As an intrinsic magnetic topological insulator with magnetic order and non-trivial topological structure, MnBi₂Te₄ is an ideal material for studying exotic topological states such as quantum anomalous Hall effect and topological axion insulating states. Here, we carry out magnetic and electrical transport measurements on (Mn_1−xGe_x)Bi₂Te₄ (x = 0, 0.15, 0.30, 0.45, 0.60, and 0.75) single crystals. It is found that with increasing x, the dilution of magnetic moments gradually weakens the antiferromagnetic exchange interaction. Moreover, Ge doping reduces the critical field of ferromagnetic ordering, which may provide a possible way to implement the quantum anomalous Hall effect at lower magnetic field. Electrical transport measurements suggest that electrons are the dominant charge carriers, and the carrier density increases with the Ge doping ratio. Additionally, the Kondo effect is observed in the samples with x = 0.45, 0.60, and 0.75. Our results suggest that doping germanium is a viable way to tune the magnetic and electrical transport properties of MnBi₂Te₄, opening up the possibility of future applications in magnetic topological insulators.

作为一种具有磁序和非平凡拓扑结构的本征磁拓扑绝缘体，MnBi ₂ Te ₄ 是研究量子反常霍尔效应和拓扑轴子等奇异拓扑态的理想材料绝缘状态。在这里，我们对 (Mn _1−x Ge _x )Bi ₂ Te ₄ (x = 0, 0.15、0.30、0.45、0.60 和 0.75）单晶。发现随着x的增加，磁矩的稀释逐渐减弱反铁磁交换相互作用。此外，Ge掺杂降低了铁磁有序的临界场，这可能为在较低磁场下实现量子反常霍尔效应提供可能的途径。电传输测量表明电子是主要的载流子，载流子密度随着Ge掺杂比例的增加而增加。此外，在 x = 0.45、0.60 和 0.75 的样品中观察到近藤效应。我们的结果表明，掺杂锗是调节 MnBi ₂ Te ₄ 磁和电传输特性的可行方法，为未来在磁拓扑绝缘体中的应用开辟了可能性。