Institute of Applied Mechanics, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei 106, Taiwan.
Nanoscale. 2015 Jun 28;7(24):10648-54. doi: 10.1039/c5nr01821h. Epub 2015 May 29.
As an intrinsic thermally anisotropic material, the thermal properties of phosphorene must vary with respect to the crystal chirality. Nevertheless, previous studies of heat transfer in phosphorene have been limited to the 0.0° (zigzag, ZZ) and 90.0° (armchair, AC) chiralities. In this study, we investigate the orientation-dependent thermal transport in phosphorene sheets with a complete set of crystal chirality ranging from 0.0° to 90.0° using the Boltzmann transport equation (BTE) associated with the first-principles calculations. It was found that in the phosphorene sheets, the intrinsic thermal conductivity is a smooth monotonic decreasing function of the crystal chirality, which exhibits sinusoidal behavior bounded by the two terminated values 48.9 (0.0°) and 27.8 (90.0°) W m(-1) K(-1). The optical modes have unusually large contributions to heat transfer, which account for almost 30% of the total thermal conductivity of phosphorene sheets. This is because the optical phonons have comparable group velocities and relaxation times to the acoustic phonons.
作为一种本征热各向异性材料，磷烯的热物性必须随晶体手性而变化。然而，以前对磷烯中热传递的研究仅限于 0.0°（锯齿，ZZ）和 90.0°（扶手椅，AC）手性。在这项研究中，我们使用与第一性原理计算相关的玻尔兹曼输运方程（BTE），研究了从 0.0°到 90.0°的完整晶体手性范围内磷烯片的各向异性热输运。结果表明，在磷烯片中，本征热导率是晶体手性的光滑单调递减函数，其表现出由两个终止值 48.9（0.0°）和 27.8（90.0°）W m(-1) K(-1) 限定的正弦行为。光学模式对热传递有异常大的贡献，占磷烯片总热导率的近 30%。这是因为光学声子与声学声子具有相当的群速度和弛豫时间。
