The study of phonon scattering processes is urgent for advancing the thermoelectric material with low thermal conductivity for commercial application. In this work, Raman scattering spectroscopy is utilized to quantify the temperature dependence of vibrational modes in ZrTe5 crystals, which enables the investigation on anharmonic contributions. We mainly focus on the temperature range from 80 up to 400 K due to noticeable surface oxidation at higher temperature. The phonon behaviors can be fully described by the model considering two mechanisms of the lattice thermal expansion effects and intrinsic anharmonicity. The four‐phonon processes are non‐negligible and even stronger than the three‐phonon processes at high temperature. The phonon lifetime is greatly reduced by the enhancement of phonon scattering, contributing to the low thermal conductivity in ZrTe5 single crystals.

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The understanding of phonon–phonon anharmonic effect in HfTe5 is essential not only for fundamental scientific interest but also for its potential thermoelectric applications. Here, rectangular ribbon‐shaped HfTe5 single crystals have been grown. Raman spectroscopy is further utilized to investigate the phonon anharmonicity of HfTe5 by quantifying the temperature dependence of the phonon mode softening and broadening. We focus on the temperature range from 80 up to 400 K since obvious surface oxidation occurs at higher temperatures. It is found that four phonon anharmonic effects are non‐negligible. The phonon lifetime is greatly reduced by the enhancement of phonon scattering, resulting in the low thermal conductivity in HfTe5 single crystals.

For engineering of van der Waals antiferromagnetic material FePSe3 and expanding its potential technological promise in spintronic fields, a detailed knowledge of the underlying physics of vibrational phonon modes and their coupling with the spin degree of freedom are undoubtedly needed. In this work, by angle-resolved polarized Raman spectroscopy in corroboration with first-principles calculation, the Raman modes of bulk FePSe3 have been rationally assigned, which clarify the ambiguity about symmetry identification of some Raman-active modes in previous studies. Moreover, through detailed temperature-dependent Raman scattering experiments, the abnormal shift of the frequency, linewidth, and integrated intensity across the Néel temperature have been identified for phonon modes associating with a non-magnetic [P2Se6]4- cluster. This can be well explained with the assistance of the spin-phonon coupling mechanism that involves the variation of the d electron transfer with lattice vibration in magnetic materials. Our results are helpful for uncovering the rich physics in FePSe3 and also for enriching the further understanding of magnetic van der Waals materials down to the 2D limit.