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arXiv · 2601.11502

Raman scattering fingerprints of the charge density wave state in one-dimensional NbTe$_4$

Natalia Zawadzka·Cem Sevik·Zahir Muhammad·Zia Ur Rehman·Weisheng Zhao·Adam Babiński·Maciej R. Molas
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Abstract

Charge-density waves (CDWs) are ordered quantum states of conduction electrons accompanied by periodic lattice distortions. Raman scattering (RS) spectroscopy is therefore well suited for probing CDW-induced structural modulations. We investigate the CDW state in quasi-one-dimensional NbTe$_4$ using RS spectroscopy. At $T$=5~K, the resonantly enhanced Raman spectrum exhibits 25 phonon modes. Polarization-dependent measurements reveal a strong coupling between phonon-mode symmetry and crystallographic symmetry, with modes polarized parallel or perpendicular to the crystallographic $c$-axis, along which the one-dimensional structure is elongated. Temperature-dependent RS measurements identify a transition between commensurate and incommensurate CDW phases, accompanied by pronounced thermal hysteresis, with transition temperatures of approximately 45~K upon cooling and 90~K upon warming. The hysteresis width depends on the warming rate, indicating a finite nucleation rate of CDW domains and suggesting potential relevance for memory-device applications.

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Natalia Zawadzka, Cem Sevik, Zahir Muhammad, Zia Ur Rehman, Weisheng Zhao, Adam Babiński, Maciej R. Molas. 2026-01-16. Raman scattering fingerprints of the charge density wave state in one-dimensional NbTe$_4$. https://doi.org/10.1063/5.0323255

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