Effective magnetic fields from optically driven chiral phonons

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Event details

Date 30.08.2023
Hour 11:0012:00
Speaker Prof. Dominik Juraschek
School of Physics and Astronomy
Tel Aviv University
Location
Category Conferences - Seminars
Event Language English

In dielectric materials, chiral phonons carry magnetic moments that are induced by orbital charge currents of the ions [1,2], and various coupling mechanisms, including electron-phonon, spin-phonon, and orbit-phonon coupling, can enhance these phonon magnetic moments up to the order of a Bohr magneton. When the chiral phonons are driven coherently with an ultrashort laser pulse, macroscopic effective magnetic fields can be induced in the material that follow the phenomenology of a phonon inverse Faraday or phonon Barnett effect [3-6]. Here, we present three examples of how these effective magnetic fields can be utilized: First, chiral phonons in paramagnetic rare-earth trihalides are able to create giant effective magnetic fields of potentially up to 100 T that polarize the spins in the material [7]. Second, the effective magnetic field produced by chiral phonons can rectify spin precession in antiferromagnets, leading to the quasistatic generation of magnetization through a transiently induced weak ferromagnetic state [8]. Third, the phonon magnetic moment can be resonantly coupled to with the magnetic field component of light, leading to a whole variety of new phenomena, including the excitation of circularly polarized phonons with linearly polarized light, phononic frequency up-conversion covering several orders of magnitude, and the excitation of Raman-active phonons without Raman scattering [9].
[1] D. Juraschek, M. Fechner, A. Balatsky, N. Spaldin, Phys. Rev. Materials, 1, 014401
(2017)
[2] D. Juraschek, N. Spaldin, Phys. Rev. Materials, 3, 064405 (2019)
[3] D. Juraschek, P. Narang, N. Spaldin, Phys. Rev. Research, 2, 043035 (2020)
[4] M. Basini, M. Pancaldi, B. Wehinger, M. Udina, T. Tadano, M. C. Hoffmann, A. V.
Balatsky and S. Bonetti, arXiv:2210.01690
[5] C. S. Davies, F. G. N. Fennema, A. Tsukamoto, I. Razdolski, A. V. Kimel and A.
Kirilyuk, arXiv:2305.11551
[6] J. Luo, T. Lin, J. Zhang, X. Chen, E. R. Blackert, R. Xu, B. I. Yakobson and H. Zhu,
arXiv:2306.03852
[7] D. Juraschek, T. Neuman, P. Narang, Phys. Rev. Research, 4, 013129 (2022)
[8] T. Kahana and D. M. Juraschek, arXiv:2305.18656
[9] D. M. Juraschek and M. Fechner, in preparation
 

Practical information

  • General public
  • Free

Organizer

  • Prof. Gregor Jotzu
    Dynamic Quantum Materials Laboratory
    STI-IMX-DQLM

Contact

  • emanuela.mancianti@epfl.ch

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