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arXiv · 2405.07853

Phonon and magnon dynamics across antiferromagnetic transition in 2D layered van der Waals material CrSBr

E. Uykur·A. A. Tsirlin·F. Long·M. Wenzel·M. Dressel·K. Mosina·Z. Sofer·M. Helm·S. Zhou
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Abstract

We report temperature-dependent reflectivity spectra of the layered van der Waals magnet CrSBr in the far-infrared region. Polarization-dependent measurements resolve the vibrational modes along the E$\|a$- and $b$-axes and reveal the clear structural anisotropy. While the $a$-axis phonons notably harden on cooling, the $b$-axis phonon frequencies are almost temperature-independent. A phonon splitting due to the antiferromagnetic phase transition is observed for the 180~cm$^{-1}$ $a$-axis vibrational mode, accompanied by a phonon softening below $T_N$. Furthermore, an additional mode with strong magnetic characteristics at $\sim$360~cm$^{-1}$ is identified and attributed to the magnon excitation of CrSBr.

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E. Uykur, A. A. Tsirlin, F. Long, M. Wenzel, M. Dressel, K. Mosina, Z. Sofer, M. Helm, S. Zhou. 2024-05-13. Phonon and magnon dynamics across antiferromagnetic transition in 2D layered van der Waals material CrSBr. https://arxiv.org/abs/2405.07853

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