论文标题
拓扑绝缘子chalcogenide bi $ _ {2} $ se $ _ {3} $中4 $ f $电子的磁相互作用
Magnetic interactions of 4$f$ electrons in the topological insulator chalcogenide Bi$_{2}$Se$_{3}$
论文作者
论文摘要
拓扑绝缘子的间隙打开机制，量子异常的霍尔效应和轴心物理学仍在提出开放问题，并且非常需要了解磁性在拓扑中的作用的显微镜观点。在这项工作中，我们通过电子旋转共振（ESR）以及互补的大量测量进行了微观研究（bi $ _ {1-x} $ gd $ _ {x} $ _ {x} $ _ {2} $ _ {2} $ _ {2} $ _ Se $ _ {3} $ _ {3} $ x $ x $ x $ x $ = 0.00，我们对GD $^{3+} $旋转动力学的分析表明，Fermi表面没有显着变化，这是GD $^{3+} $浓度的函数，这表明4 $ f $磁力与由过渡金属（$ d $电子）替代品引起的非局部效应不同。此外，我们观察到GD $^{3+} $ ESR光谱的异常演变是应用磁场的函数，考虑到GD $^{3+} $ 4 $ f $电子与诸如SE空缺等GD $^{3+} $ 4 $ F $电子之间的磁相互作用。这种相互作用将引起围绕GD $^{3+} $离子的局部弱反静电效应。由于与$ d $电子相比，该系统中GD $^{3+} $ 4 $ f $电子磁性的特定细节，因此可以观察到这种机制。我们的工作指出，该模型拓扑绝缘子中的稀土取代是探索轴突绝缘系统的有前途的途径。
The gap opening mechanism of a topological insulator, the quantum anomalous Hall effect and the axion physics are still pressing open questions and a microscopic viewpoint to further understand the role of magnetism in topology is highly desirable. In this work we have performed a microscopic investigation, by means of electron spin resonance (ESR) along with complementary bulk measurements, on the chalcogenide (Bi$_{1-x}$Gd$_{x}$)$_{2}$Se$_{3}$ ($x$ = 0, 0.001, 0.002 and 0.006). Our analysis of the Gd$^{3+}$ spin dynamics reveal no significant change of the Fermi surface as a function of Gd$^{3+}$ concentration, which indicates that the 4$f$ magnetism is different from the non-local effects induced by transition metals ($d$ electrons) substitutions. Additionally, we observe an unusual evolution of the Gd$^{3+}$ ESR spectra as a function of the applied magnetic field, which we discuss considering the magnetic interaction between Gd$^{3+}$ 4$f$ electrons and impurity centers such as Se vacancies. This interaction would give rise to a local weak antilocalization effect surrounding the Gd$^{3+}$ ions. Such mechanism is observable due to particular details of the Gd$^{3+}$ 4$f$ electrons magnetism in this system compared to $d$ electrons. Our work points out that rare earth substitutions in this model topological insulator is a promising path to explore the axion insulating systems.
