Tracing Dirac points of topological surface states by ferromagnetic resonance

Pietanesi, L and Marganska, M and Mayer, T and Barth, M and Chen, L and Zou, J and Weindl, A and Liebig, A and Díaz-Pardo, R and Suri, D and Schmid, F and Gie�ibl, FJ and Richter, K and Tserkovnyak, Y and Kronseder, M and Back, CH (2024) Tracing Dirac points of topological surface states by ferromagnetic resonance. In: Physical Review B, 109 (6).

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Abstract

Ferromagnetic resonance is used to reveal features of the buried electronic band structure at interfaces between ferromagnetic metals and topological insulators. By monitoring the evolution of magnetic damping, the application of this method to a hybrid structure consisting of a ferromagnetic layer and a 3D topological insulator reveals a clear fingerprint of the Dirac point and exhibits additional features of the interfacial band structure not otherwise observable. The underlying spin-pumping mechanism is discussed in the framework of dissipation of angular momentum by topological surface states (TSSs). Tuning of the Fermi level within the TSS was verified both by varying the stoichiometry of the topological insulator layer and by electrostatic backgating and the damping values obtained in both cases show a remarkable agreement. The high-energy resolution of this method additionally allows us to resolve the energetic shift of the local Dirac points generated by local variations of the electrostatic potential. Calculations based on the chiral tunneling process naturally occurring in TSSs agree well with the experimental results. © 2024 American Physical Society.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Additional Information:	The copyright for this article belongs to the American Physical Society.
Keywords:	Band structure; Damping; Electric insulators; Electrostatics; Ferromagnetic resonance; Ferromagnetism; Surface states; Topological insulators; Topology, Dirac point; Electronic band structure; Ferromagnetic layers; Hybrid structure; Insulator layer; Magnetic damping; Metal insulators; Pumping mechanism; Spin-pumping; Topological insulators, Ferromagnetic materials
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	07 Apr 2024 07:12
Last Modified:	07 Apr 2024 07:12
URI:	https://eprints.iisc.ac.in/id/eprint/84703

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