Abstract We study magneto-transport phenomena in two rare-earth doped topological insulators, SmxFexSb2-2xTe3 and SmxBi2-xTe2Se single crystals. The magneto-transport behaviours in both compounds exhibit a novel crossover between weak anti-localization (positive magnetoresistance) and weak localization (negative magnetoresistance) with changes in temperatures and magnetic fields. The weak localization is caused by rare-earth-doping induced magnetization, and the weak anti-localization originates from topologically protected surface states. The transition from weak localization to weak anti-localization demonstrates a gap opening at the Dirac point of the surface states in the quantum diffusive regime. This work demonstrates an effective way to manipulate the magneto-transport properties of the topological insulators by rare-earth element doping. Magnetometry measurements indicate that the Sm-dopant alone is paramagnetic, whereas the co-doped Fe-Sm state has short-range antiferromagnetic order. Our results demonstrate the potential to realize exotic topological effects and magneto-electric effects in gapped surface states of rare earth doped topological insulators.

中文翻译：

---

在稀有掺杂 TRS 保护拓扑绝缘体中从弱定域到反定域的交叉

摘要 我们研究了两种稀土掺杂拓扑绝缘体 SmxFexSb2-2xTe3 和 SmxBi2-xTe2Se 单晶中的磁输运现象。随着温度和磁场的变化，这两种化合物的磁传输行为在弱反定位（正磁阻）和弱定位（负磁阻）之间表现出新的交叉。弱局域化是由稀土掺杂引起的磁化引起的，弱反局域化源于受拓扑保护的表面态。从弱局域化到弱反局域化的转变表明量子扩散区域中表面态的狄拉克点处的间隙开口。这项工作展示了一种通过稀土元素掺杂来操纵拓扑绝缘体的磁传输特性的有效方法。磁力测量表明，单独的 Sm 掺杂剂是顺磁性的，而共掺杂的 Fe-Sm 状态具有短程反铁磁有序。我们的结果证明了在稀土掺杂拓扑绝缘体的有隙表面状态中实现奇异拓扑效应和磁电效应的潜力。