SPICE Workshop on Ferrons and Magnons: friends or foes? July 7th - 9th, 2026
Xiaoyang Zhu
Excitation of ordered quantum phases gives rise to collective modes and quasiparticles, as exemplified by spin waves and magnons emerging from magnetic order. Extending this paradigm to ferroelectric materials suggests the existence of polarization waves and their fundamental quanta, ferrons. Here, we report the generation and transport of polarization waves, i.e., coherent ferrons, in the van der Waals ferroelectric material NbOI2 [1-3]. Upon excitation by a short laser pulse, the polarization wave emits intense and narrow-band terahertz (THz) radiation at the ferroelectric transverse optical phonon frequency, modulates the ferroelectric order parameter, and propagates uniaxially along the polar axis at hypersonic velocities of ~105 m/s. These long-lived, uniaxial, and dipole-carrying polarization waves may find applications in narrow-band THz emission, ferronic information processing, and coherent electric control.
References
[1] Jeongheon Choe, Taketo Handa, Chun-Ying Huang, André Koch Liston, Jordan Cox, Jonathan Stensberg, Yongseok Hong, Daniel G. Chica, Ding Xu, Fuyang Tay, Samra Husremovic, Vinícius da S. L. Avelar, Eric A. Arsenault, Zhuquan Zhang, James McIver, Dmitri N. Basov, Milan Delor, Xavier Roy, X.-Y. Zhu, “Observation of coherent ferrons,” 2025, arXiv:2505.22559.
[2] Taketo Handa, Chun-Ying Huang, Yiliu Li, Nicholas Olsen, Daniel G Chica, David D Xu, Felix Sturm, James W McIver, Xavier Roy, X.-Y. Zhu, “Terahertz Emission from Giant Optical Rectification in a van der Waals Material,” Nature Mat. 2025, 24, 1203-1208.
[3] Chun-Ying Huang, Daniel G Chica, Zhi-Hao Cui, Taketo Handa, Morgan Thinel, Nicholas Olsen, Yufeng Liu, Michael E Ziebel, Guiying He, Yinming Shao, Connor A Occhialini, Jonathan Pelliciari, Dmitri N Basov, Matthew Sfeir, Abhay Pasupathy, Valentina Bisogni, David R Reichman, Xavier Roy, Xiaoyang Zhu, “Coupling of electronic transition to ferroelectric order in a 2D semiconductor,” Nature Commun. 2025, 16, 1896.