The charge density wave (CDW), as a hallmark of vanadium-based kagome superconductor AV3Sb5 (A = K, Rb, Cs), has attracted intensive attention. However, the fundamental controversy regarding the underlying mechanism of CDW therein persists. Recently, the vanadium-based bi-layered kagome metal ScV6Sn6, reported to exhibit a long-range charge order below 94 K, has emerged as a promising candidate to further clarify this core issue. Here, employing micro-focusing angle-resolved photoemission spectroscopy ({\mu}-ARPES) and first-principles calculations, we systematically studied the unique CDW order in vanadium-based bi-layered kagome metals by comparing ScV6Sn6 with its isostructural counterpart YV6Sn6, which lacks a CDW ground state. Combining ARPES data and the corresponding joint density of states (DOS), we suggest that the VHS nesting mechanism might be invalid in these materials. Besides, in ScV6Sn6, we identified multiple hybridization energy gaps resulting from CDW-induced band folding, along with an anomalous band dispersion, implying a potential electron-phonon coupling driven mechanism underlying the formation of the CDW order. Our finding not only comprehensively maps the electronic structure of V-based bi-layer kagome metals but also provide constructive experimental evidence for the unique origin of CDW in this system.
@article{arxiv.2402.03765,
title = {Unveiling the charge density wave mechanism in vanadium-based Bi-layered kagome metals},
author = {Yi-Chen Yang and Soohyun Cho and Tong-Rui Li and Xiang-Qi Liu and Zheng-Tai Liu and Zhi-Cheng Jiang and Jian-Yang Ding and Wei Xia and Zi-Cheng Tao and Jia-Yu Liu and Wen-Chuan Jing and Yu Huang and Yu-Ming Shi and Soonsang Huh and Takeshi Kondo and Zhe Sun and Ji-Shan Liu and Mao Ye and Yi-Lin Wang and Yan-Feng Guo and Da-Wei Shen},
journal= {arXiv preprint arXiv:2402.03765},
year = {2024}
}