Chirality selective magnon-phonon hybridization and magnon-induced chiral phonons in a layered zigzag antiferromagnet

• Published in: Nature communications 2023-06, Vol.14 (1), p.3396-3396, Article 3396
• Main Authors: Cui, Jun, Boström, Emil Viñas, Ozerov, Mykhaylo, Wu, Fangliang, Jiang, Qianni, Chu, Jiun-Haw, Li, Changcun, Liu, Fucai, Xu, Xiaodong, Rubio, Angel, Zhang, Qi
• Format: Article
• Language: English
• Subjects: 639/301/357/1018; 639/624/400/1101; 639/766/119/997; Angular momentum; Antiferromagnetism; Chirality; Circular polarization; Coupling; Electrons; Elementary excitations; Excitation; First principles; Humanities and Social Sciences; Hybridization; Hybridization, Genetic; Lattice vibration; Magnetic Fields; Magnetic properties; Magnons; Motion; multidisciplinary; Nucleic Acid Hybridization; Phonons; Polarons; Raman spectroscopy; Science; Science (multidisciplinary); Vibrations
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-39123-y

Two-dimensional (2D) magnetic systems possess versatile magnetic order and can host tunable magnons carrying spin angular momenta. Recent advances show angular momentum can also be carried by lattice vibrations in the form of chiral phonons. However, the interplay between magnons and chiral phonons as well as the details of chiral phonon formation in a magnetic system are yet to be explored. Here, we report the observation of magnon-induced chiral phonons and chirality selective magnon-phonon hybridization in a layered zigzag antiferromagnet (AFM) FePSe 3 . With a combination of magneto-infrared and magneto-Raman spectroscopy, we observe chiral magnon polarons (chiMP), the new hybridized quasiparticles, at zero magnetic field. The hybridization gap reaches 0.25 meV and survives down to the quadrilayer limit. Via first principle calculations, we uncover a coherent coupling between AFM magnons and chiral phonons with parallel angular momenta, which arises from the underlying phonon and space group symmetries. This coupling lifts the chiral phonon degeneracy and gives rise to an unusual Raman circular polarization of the chiMP branches. The observation of coherent chiral spin-lattice excitations at zero magnetic field paves the way for angular momentum-based hybrid phononic and magnonic devices. Phonons are the collective excitations of the lattice of a material, and can, in the case of chiral phonons, carry angular momentum, allowing for strong coupling to the magnetic properties of the material. Here, Cui, Bostrom and co-authors observe chiral magnon polarons, the hybridized quasiparticles of chiral phonons and magnons, in the van der Waals antiferromagnet FePSe 3 .