SKM 2021 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 2: Focus Session: Magnon Polarons - Magnon-Phonon Coupling and Spin Transport (joint session MA/HL)

MA 2.6: Hauptvortrag

Montag, 27. September 2021, 15:45–16:15, H5

Magnon-Polarons in different flavors: (anti)ferromagnetic to topological — •Akashdeep Kamra — Condensed Matter Physics Center (IFIMAC) and Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain

Due to magnetoelastic coupling, magnons and phonons in a magnet can combine to form hybrid quasiparticles, inheriting properties from both, called magnon-polarons. We will begin by examining and clarifying the essential requirements for their hybridization in terms of the spin conservation laws and the nature of the magnetoelastic coupling. This will allow us to deduce the properties, such as spin, of the magnon-polarons thus formed and provide guidance on how to engineer magnon-polarons. In carrying out this general discussion, we will analyze the cases of magnon-polarons in ferromagnets as examples. Then, we will apply the general principles developed to the cases of antiferromagnets and topological magnonic insulators thereby demonstrating magnon-polarons with novel, tunable, and chiral properties. We will conclude our discussion with recent experiments suggesting spin-phonon coupling to underlie collective quantum phenomena in the high-Tc superconductor YBCO.

References: [1] A. Kamra, H. Keshtgar, P. Yan, and G. E. W. Bauer. Phys. Rev. B 91, 104409 (2015). [2] H. T. Simensen, R. E. Troncoso, A. Kamra, and A. Brataas. Phys. Rev. B 99, 064421 (2019). [3] E. Thingstad, A. Kamra, A. Brataas, and A. Sudbø. Phys. Rev. Lett. 122, 107201 (2019).