Dresden 2020 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 38: Focus Session: Magnon Polarons – Magnon-Phonon Coupling and Spin Transport (joint session MA/HL)

HL 38.7: Invited Talk

Wednesday, March 18, 2020, 12:15–12:45, HSZ 04

Magnon-Polarons in different flavors: (anti)ferromagnetic to topological — •Akashdeep Kamra — Center for Quantum Spintronics, Norwegian University of Science and Technology, Trondheim, Norway

Due to magnetoelastic coupling, magnons and phonons in a magnetic material can combine to form hybrid quasiparticles, inheriting properties from both, called magnon-polarons. In this talk, we will examine and clarify the essential requirements for their hybridization in terms of the typical 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 by examining the general symmetries of the material and excitation propagation direction. In carrying out this general discussion, we will refer to the cases of magnon-polarons in ferromagnets as examples. What is their spin? What kind of phonons can the magnons hybridize with? 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 the discussion with an outlook on some open questions and possible future avenues in this context.
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).