Multiple Softening Q-vectors Driving a Cascade of CDW Phases in 1T−VSe2
Abstract
Charge density wave (CDW) formation in two-dimensional materials is governed by complex competing lattice instabilities that remain incompletely understood. Here, we investigate the structural evolution of monolayer 1T−VSe2 using first-principles electronic and phonon calculations. The pristine phase exhibits several imaginary-frequency phonon modes associated with dominant instability wave vectors QCDW, which generate the first-generation CDW phases. Subsequent phonon analyses reveal that several of these intermediate structures remain dynamically unstable and undergo further symmetry-lowering distortions into larger superstructures. Through iterative phonon-driven relaxations, we identify multiple transformation pathways that converge toward the same low-energy 2√3×4 CDW configuration. Although these pathways originate from distinct intermediate CDW states, they ultimately reach nearly degenerate energetically stable phases, demonstrating that different phonon-driven routes can lead to the same ground-state configuration. The results establish a unified phonon-driven cascade mechanism for hierarchical CDW formation in monolayer 1T−VSe2 and provide a systematic framework for understanding competing ordered phases in low-dimensional quantum materials.
Versions
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BibTeX
@misc{li2026multiple,
title = {{Multiple Softening Q-vectors Driving a Cascade of CDW Phases in $\mathrm1T-VSe_2$}},
author = {Zheng-Hong Li and Yung-Ting Lee and Yu-Chan Tai and Cheng-Tien Chiang and Chien-Cheng Kuo and Meng-Kai Lin and Chun-Liang Lin and Hung-Chung Hsueh and Ming-Chiang Chung and Po-Tuan Chen and Chi-Cheng Lee},
howpublished = {arXiv},
year = {2026},
month = may,
doi = {10.48550/arxiv.2605.13458},
eprint = {2605.13458},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.13458},
}
RIS
TY - UNPB
TI - Multiple Softening Q-vectors Driving a Cascade of CDW Phases in 1T−VSe_2
AU - Zheng-Hong Li
AU - Yung-Ting Lee
AU - Yu-Chan Tai
AU - Cheng-Tien Chiang
AU - Chien-Cheng Kuo
AU - Meng-Kai Lin
AU - Chun-Liang Lin
AU - Hung-Chung Hsueh
AU - Ming-Chiang Chung
AU - Po-Tuan Chen
AU - Chi-Cheng Lee
PY - 2026
DA - 2026/05/13
PB - arXiv
DO - 10.48550/arxiv.2605.13458
UR - https://arxiv.org/abs/2605.13458
AB - Charge density wave (CDW) formation in two-dimensional materials is governed by complex competing lattice instabilities that remain incompletely understood. Here, we investigate the structural evolution of monolayer 1T−VSe_2 using first-principles electronic and phonon calculations. The pristine phase exhibits several imaginary-frequency phonon modes associated with dominant instability wave vectors Q_CDW, which generate the first-generation CDW phases. Subsequent phonon analyses reveal that several of these intermediate structures remain dynamically unstable and undergo further symmetry-lowering distortions into larger superstructures. Through iterative phonon-driven relaxations, we identify multiple transformation pathways that converge toward the same low-energy 2√3×4 CDW configuration. Although these pathways originate from distinct intermediate CDW states, they ultimately reach nearly degenerate energetically stable phases, demonstrating that different phonon-driven routes can lead to the same ground-state configuration. The results establish a unified phonon-driven cascade mechanism for hierarchical CDW formation in monolayer 1T−VSe_2 and provide a systematic framework for understanding competing ordered phases in low-dimensional quantum materials.
ER -