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arXiv · 2502.05170

Observation of a dynamic magneto-chiral instability in photoexcited tellurium

Yijing Huang·Nick Abboud·Yinchuan Lv·Penghao Zhu·Azel Murzabekova·Changjun Lee·Emma A. Pappas·Dominic Petruzzi·Jason Y. Yan·Dipanjan Chauduri·Peter Abbamonte·Daniel P. Shoemaker·Rafael M. Fernandes·Jorge Noronha·Fahad Mahmood
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Abstract

In a system of charged chiral fermions driven out of equilibrium, an electric current parallel to the magnetic field can generate a dynamic instability by which electromagnetic waves become amplified. Whether a similar instability can occur in chiral solid-state systems remains an open question. Using time-domain terahertz (THz) emission spectroscopy, we detect signatures of what we dub a ``dynamic magneto-chiral instability" in elemental tellurium, a structurally chiral crystal. Upon transient photoexcitation in a moderate external magnetic field, tellurium emits THz radiation consisting of coherent modes that amplify over time. An explanation for this amplification is proposed using a theoretical model based on a dynamic instability of electromagnetic waves interacting with infrared-active oscillators of impurity acceptor states in tellurium to form an amplifying polariton. Our work not only uncovers the presence of a magneto-chiral instability but also highlights its promise for THz-wave amplification in chiral materials.

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Yijing Huang, Nick Abboud, Yinchuan Lv, Penghao Zhu, Azel Murzabekova, Changjun Lee, Emma A. Pappas, Dominic Petruzzi, Jason Y. Yan, Dipanjan Chauduri, Peter Abbamonte, Daniel P. Shoemaker, Rafael M. Fernandes, Jorge Noronha, Fahad Mahmood. 2025-02-07. Observation of a dynamic magneto-chiral instability in photoexcited tellurium. https://doi.org/10.1038/s41567-025-03145-8

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