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TT: Fachverband Tiefe Temperaturen

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

TT 63.4: Invited Talk

Thursday, March 21, 2024, 11:15–11:45, H 1058

Orbital magnetic moment of phonons in diamagnetic and paraelectric perovskites — Filip Kadlek¹, Christelle Kadlek¹, •Martina Basini^2,3, Sergey Kovalev⁴, Jan-Christoph Deinert⁴, Stefano Bonetti^1,5, and Stanislav Kamba¹ — ¹Institute of Physics of the Czech Academy of Sciences, Praha, Czech Republic — ²Department of Physics, Stockholm University, Stockholm, Sweden — ³Deparment of Materials and Nanophysics, KTH Royal Institute of Technology, Stockholm Sweden — ⁴Helmholz Zentrum Dresden-Rossendorf, Germany — ⁵Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, Venice, Italy

In the present work, we demonstrate transient magnetism in KTaO₃ induced by chiral phonons. In particular, the infrared-active soft phonon was circularly excited by means of intense quasi-monochromatic THz pulses produced by the TELBE facility and the magnetic moment was probed by magneto-optical Faraday effect. The evidence will be compared with our previous results on SrTiO₃. We anticipate that, contrary to SrTiO₃, KTaO₃ does not undergo any structural phase transition at low temperature so that we could efficiently excite the soft phonon below 100K, where the phonon effective charge is larger and a higher value of the induced orbital magnetic moments per unit cell is expected.

Keywords: Chiral phonons; Dynamical muliferroicity; Phonon dynamics; Phonon magnetic moment; Ulrafast Barnett Effect