Sun Yang, Wang Liya, Wang Chengyuan, Tang Chun
Faculty of Civil Engineering and Mechanics, Jiangsu University, #301 Xuefu Rd, Zhenjiang, 212013, People's Republic of China.
Nanotechnology. 2021 Feb 19;32(8):085702. doi: 10.1088/1361-6528/abc98f.
Blue phosphorus is an emerging 2D material that exhibits finite electronic band gap and may find promising applications in advanced semiconducting devices. Comparing to its allotrope, black phosphorus, mechanical properties of blue phosphorus have not been explored in detail. Here we report molecular dynamics simulations of mechanical responses of blue phosphorus under uniaxial tensile, biaxial tensile and shear loadings. It is found that blue phosphorus shows less anisotropic effect as compared to black phosphorus, the room temperature Young's modulus is about 122.3 GPa and 121.6 GPa along armchair and zigzag directions, respectively, shear modulus is about 27.1 GPa and 28.6 GPa, respectively, along armchair and zigzag directions. Temperature effect on mechanical responses is also systematically studied within a range of 5-400 K. It is found that temperature reduces both Young's modulus and fracture strain and fracture strength of blue phosphorus, owing to the interplay between thermal energy and strain energy applied to the models. Brittle fracture mode is found in blue phosphorus in all loading conditions, with varied crack nucleation and propagation modes. The role of strain rate on the mechanical properties is examined and found to systematically modify the ultimate stress and ultimate strain of BlueP. Structural details including bond length and bond angle variations to external strain are analyzed to gain deeper insights into the underlying mechanisms.
蓝磷是一种新兴的二维材料，具有有限的电子带隙，在先进半导体器件中可能有广阔的应用前景。与它的同素异形体黑磷相比，蓝磷的力学性能尚未得到详细研究。在此，我们报告了蓝磷在单轴拉伸、双轴拉伸和剪切载荷下力学响应的分子动力学模拟。结果发现，与黑磷相比，蓝磷表现出较小的各向异性效应，室温下沿扶手椅方向和锯齿方向的杨氏模量分别约为122.3 GPa和121.6 GPa，剪切模量沿扶手椅方向和锯齿方向分别约为27.1 GPa和28.6 GPa。还在5 - 400 K的温度范围内系统地研究了温度对力学响应的影响。结果发现，由于施加在模型上的热能和应变能之间的相互作用，温度降低了蓝磷的杨氏模量、断裂应变和断裂强度。在所有加载条件下，蓝磷均呈现脆性断裂模式，裂纹形核和扩展模式各不相同。研究了应变速率对力学性能的作用，发现其能系统地改变蓝磷的极限应力和极限应变。分析了包括键长和键角随外部应变的变化在内的结构细节，以更深入地了解其潜在机制。
