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 NbTe4 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.
@article{arxiv.2601.11502,
title = {Raman scattering fingerprints of the charge density wave state in one-dimensional NbTe$_4$},
author = {Natalia Zawadzka and Cem Sevik and Zahir Muhammad and Zia Ur Rehman and Weisheng Zhao and Adam Babiński and Maciej R. Molas},
journal= {arXiv preprint arXiv:2601.11502},
year = {2026}
}