Patterns and driving forces of dimensionality-dependent charge density waves in 2H-type transition metal dichalcogenides

• Published in: Nature communications Vol. 11; no. 1; p. 2406
• Main Authors: Lin, Dongjing, Li, Shichao, Wen, Jinsheng, Berger, Helmuth, Forró, László, Zhou, Huibin, Jia, Shuang, Taniguchi, Takashi, Watanabe, Kenji, Xi, Xiaoxiang, Bahramy, Mohammad Saeed
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.05.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 140/133; 639/301/357/1018; 639/766/119/544; 639/766/119/995; Chalcogenides; Charge density waves; Charge distribution; Charge transfer; Dependence; Humanities and Social Sciences; multidisciplinary; Niobium; Quantum phenomena; Science; Science (multidisciplinary); Tantalum; Transition metal compounds; Trends
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-15715-w

Charge density wave (CDW) is a startling quantum phenomenon, distorting a metallic lattice into an insulating state with a periodically modulated charge distribution. Astonishingly, such modulations appear in various patterns even within the same family of materials. Moreover, this phenomenon features a puzzling diversity in its dimensional evolution. Here, we propose a general framework, unifying distinct trends of CDW ordering in an isoelectronic group of materials, 2 H-MX 2 ( M = Nb, Ta and X = S, Se). We show that while NbSe 2 exhibits a strongly enhanced CDW order in two dimensions, TaSe 2 and TaS 2 behave oppositely, with CDW being absent in NbS 2 entirely. Such a disparity is demonstrated to arise from a competition of ionic charge transfer, electron-phonon coupling, and electron correlation. Despite its simplicity, our approach can, in principle, explain dimensional dependence of CDW in any material, thereby shedding new light on this intriguing quantum phenomenon and its underlying mechanisms. The dimensional dependence of charge density wave (CDW) in two-dimensional dichalcogenides remains puzzled. Here, Lin et al. study trends of CDW ordering in an isoelectronic group of materials 2 H - MX 2 and provide a unified understanding involving several microscopic factors.