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arXiv · 2211.16048

Magnetic interactions of 4$f$ electrons in the topological insulator chalcogenide Bi$_{2}$Se$_{3}$

J. C. Souza·M. Carlone·G. G. Lesseux·H. B. Pizzi·G. S. Freitas·R. R. Urbano·P. A. Venegas·P. G. Pagliuso
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Abstract

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.

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J. C. Souza, M. Carlone, G. G. Lesseux, H. B. Pizzi, G. S. Freitas, R. R. Urbano, P. A. Venegas, P. G. Pagliuso. 2022-11-29. Magnetic interactions of 4$f$ electrons in the topological insulator chalcogenide Bi$_{2}$Se$_{3}$. https://doi.org/10.1103/physrevb.106.235109

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