Axial-Bonding-Driven Dimensionality Effect on the Charge-Density Wave in NbSe2

Lin D, Ranjbar A, Li X, Huang X, Huang Y, Berger H, Forro L, Watanabe K, Taniguchi T, Belosludov RV, Kühne TD, Ding H, Bahramy MS, Xi X (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Nano Letters American Chemical Society

Book Volume: 22

Pages Range: 9389-9395

Journal Issue: 23

DOI: 10.1021/acs.nanolett.2c03280

Abstract

2H-NbSe2is a prototypical charge-density-wave (CDW) system, exhibiting such a symmetry-breaking quantum ground state in its bulk and down to a single-atomic-layer limit. However, how this state depends on dimensionality and what governs the dimensionality effect remain controversial. Here, we experimentally demonstrate a robust 3 × 3 CDW phase in both freestanding and substrate-supported bilayer NbSe2, far above the bulk transition temperature. We exclude environmental effects and reveal a strong temperature and thickness dependence of Raman intensity from an axially vibrating A1gphonon mode, involving Se ions. Using first-principles calculations, we show that these result from a delicate but profound competition between the intra- and interlayer bonding formed between Se-pzorbitals. Our results suggest the crucial role of Se out-of-plane displacement in driving the CDW distortion, revealing the Se-dominated dimensionality effect and establishing a new perspective on the chemical bonding and mechanical stability in layered CDW materials.

Involved external institutions

Nanjing University CN China (CN) Universität Paderborn DE Germany (DE) Beijing Institute of Technology (BIT) / 北京理工大学 CN China (CN) École Polytechnique Fédérale de Lausanne (EPFL) CH Switzerland (CH) National Institute of Materials Science (NIMS) JP Japan (JP) Tohoku University JP Japan (JP) University of Manchester GB United Kingdom (GB)

How to cite

APA:

Lin, D., Ranjbar, A., Li, X., Huang, X., Huang, Y., Berger, H.,... Xi, X. (2022). Axial-Bonding-Driven Dimensionality Effect on the Charge-Density Wave in NbSe2. Nano Letters, 22(23), 9389-9395. https://doi.org/10.1021/acs.nanolett.2c03280

MLA:

Lin, Dongjing, et al. "Axial-Bonding-Driven Dimensionality Effect on the Charge-Density Wave in NbSe2." Nano Letters 22.23 (2022): 9389-9395.

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