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arXiv · 2610.32797

Unconventional charge density wave order in ErTe$_{3}$: symmetry breakings and fluctuations probed by Raman scattering

Théotime Freitas·Mattia Udina·Alexandr Alekhin·Niloufar Nilforoushan·Sarah Houver·Alain Sacuto·Benito A. Gonzalez·Ian R. Fisher·Indranil Paul·Yann Gallais
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Abstract

Recent experiments have revealed unexpected mirror-symmetry breakings in the charge density-wave (CDW) state of rare-earth tritellurides, suggesting a putative ferro-axial CDW state. Here we report polarization-resolved Raman scattering measurements tracking the point-group symmetry breakings across the CDW phase transition in the rare-earth tritelluride ErTe$_3$. We show that the mirror-symmetry breakings follow closely the emergence of the CDW order, suggesting a single component CDW order parameter. Furthermore, Raman measurements in the $A_{2g}$ symmetry channel above the CDW transition temperature indicate the absence of significant ferro-axial fluctuations. We discuss the broad implications of these findings with respect to the nature of the CDW state in the tritellurides.

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Théotime Freitas, Mattia Udina, Alexandr Alekhin, Niloufar Nilforoushan, Sarah Houver, Alain Sacuto, Benito A. Gonzalez, Ian R. Fisher, Indranil Paul, Yann Gallais. 2026-10-23. Unconventional charge density wave order in ErTe$_{3}$: symmetry breakings and fluctuations probed by Raman scattering. https://arxiv.org/abs/2610.32797

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