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TT: Fachverband Tiefe Temperaturen

TT 63: Focus Session: Emerging Magnetic Phenomena from Chiral Phonons I (joint session MA/TT)

TT 63.1: Hauptvortrag

Donnerstag, 21. März 2024, 09:30–10:00, H 1058

Giant effective magnetic fields from chiral phonons — •Dominik M. Juraschek — Tel Aviv University, Tel Aviv 6997801, Israel

Chiral phonons conventionally describe circularly polarized lattice vibrations that carry angular momentum. In dielectric materials, the circular motions of the ions create a macroscopic magnetic field when driven with an ultrashort laser pulse, which has previously been shown to reach the order of millitesla. Here, we predict that this magnetic field can effectively reach up to the tesla scale, when enhanced by orbit-lattice coupling [1,2]. Our predictions have been experimentally confirmed in a recent study [3]. We demonstrate theoretically that these giant phono-magnetic fields can be utilized to generate nonequilibrium spin configurations in antiferromagnets, leading to a light-induced weak ferromagnetic state [4]. Finally, whereas the above phenomena are based on circularly polarized chiral phonons, we further demonstrate that the crystal structure can be transiently made chiral with linearly polarized phonons that are quasistatically displaced by nonlinear phonon coupling [5]. These ``linearly polarized chiral phonons'' make it possible to create chiral crystal structures on demand with implications for chiral magnetic and electronic properties. [1] Juraschek et al., PRResearch, 4, 013129 (2022) [2] S. Chaudhary, D. M. Juraschek, et al., arXiv:2306.11630 (2023) [3] J. Luo et al., Science 382, 698 (2023) [4] T. Kahana, D. A. Bustamante Lopez, and D. M. Juraschek, arXiv:2305.18656 (2023) [5] C. Romao and D. M. Juraschek, arXiv:2311.00824 (2023)

Keywords: chiral phonons; quantum materials; ultrafast dynamics; nonlinear phononics; multiferroics