Magdalena Marganska
(Institute for Theoretical Physics, Wrocław Tech)
Ferromagnetic resonance is used to reveal features of the buried electronic band structure at interfaces between ferromagnetic metals and topological insulators [1]. 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.
[1] Pietanesi et al., “Tracing Dirac points of topological surface states by ferromagnetic resonance”, Phys. Rev. B 109, 064424 (2024)
Magdalena Marganska
(Institute for Theoretical Physics, Wrocław Tech)
Adrian Weindl
(Institute for Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany)
Alexander Liebig
(Institute for Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany)
Christian Back
(Center for Quantum Engineering (ZQE), Technical University Munich, 85748 Garching, Germany)
Dhavala Suri
(Center for Nanoscience and Engineering, Indian Institute of Science, Bengaluru 560 012, India)
Florian Schmid
(Institute for Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany)
Franz Giessibl
(Institute for Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany)
Ji Zou
(Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA)
Klaus Richter
(Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany)
Laura Pietanesi
(School of Natural Sciences, Department of Physics, Technical University of Munich, 85748 Garching, Germany)
Lin Chen
(School of Natural Sciences, Department of Physics, Technical University of Munich, 85748 Garching, Germany)
Matthias Kronseder
(Institute for Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany)
Michael Barth
(Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany)
Rebeca Diaz-Pardo
(School of Natural Sciences, Department of Physics, Technical University of Munich, 85748 Garching, Germany)
Thomas Mayer
(Institute for Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany)
Yaroslav Tserkovnyak
(Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA)
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