Anisotropic Fracture of Two-Dimensional Ta<sub>2</sub>NiSe<sub>5</sub>.

Li, Binzhao; Li, Jiahao; Jiang, Wei; Wang, Yafei; Wang, Dong; Song, Li; Zhu, Yinbo; Wu, HengAn et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

Anisotropic two-dimensional materials present a diverse range of physical characteristics, making them well-suited for applications in photonics and optoelectronics. While mechanical properties play a crucial role in determining the reliability and efficacy of 2D material-based devices, the fracture behavior of anisotropic 2D crystals remains relatively unexplored. Toward this end, we herein present the first measurement of the anisotropic fracture toughness of 2D Ta<sub>2</sub>NiSe<sub>5</sub> by microelectromechanical system-based tensile tests. Our findings reveal a significant in-plane anisotropic ratio (∼3.0), accounting for crystal orientation-dependent crack paths. As the thickness increases, we observe an intriguing intraplanar-to-interplanar transition of fracture along the <i>a</i>-axis, manifesting as stepwise crack features attributed to interlayer slippage. In contrast, ruptures along the <i>c</i>-axis surprisingly exhibit persistent straightness and smoothness regardless of thickness, owing to the robust interlayer shear resistance. Our work affords a promising avenue for the construction of future electronics based on nanoribbons with atomically sharp edges.