Effect of van der Waals interactions on the structural and elastic properties of black phosphorus
Effect of van der Waals interactions on the structural and elastic properties of black phosphorus
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DOI：
10.1103/physrevb.86.035105
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发表时间：
2012-07-05
影响因子：
3.7
通讯作者：
Svane, A.
中科院分区：
文献类型：
--
作者：
Appalakondaiah, S.;Vaitheeswaran, G.;Svane, A.
采用基于密度泛函理论的第一性原理方法研究了正交黑磷的结构和弹性性质。的结构参数已被计算使用局域密度近似（LDA），广义梯度近似（GGA），并与几个色散校正，包括货车德瓦尔斯相互作用。与实验结果相比，色散修正改善了LDA和GGA的晶格参数。计算再现压力下的实验趋势，并表明，货车德瓦尔斯相互作用是最重要的结晶B轴的意义上，他们有最大的影响磷层之间的键合。弹性常数的计算，并发现与实验值吻合良好。计算的C-22弹性常数明显大于C-11和C-33参数，这意味着黑磷对应变的刚性沿着a轴比沿着B和c轴。从计算的弹性常数，力学性能，如体积模量，剪切模量，杨氏模量，泊松比得到。计算得到的拉曼激活光学声子频率及其压力变化与实验结果符合得很好。
The structural and elastic properties of orthorhombic black phosphorus have been investigated using first-principles calculations based on density functional theory. The structural parameters have been calculated using the local density approximation (LDA), the generalized gradient approximation (GGA), and with several dispersion corrections to include van der Waals interactions. It is found that the dispersion corrections improve the lattice parameters over LDA and GGA in comparison with experimental results. The calculations reproduce well the experimental trends under pressure and show that van der Waals interactions are most important for the crystallographic b axis in the sense that they have the largest effect on the bonding between the phosphorus layers. The elastic constants are calculated and are found to be in good agreement with experimental values. The calculated C-22 elastic constant is significantly larger than the C-11 and C-33 parameters, implying that black phosphorus is stiffer against strain along the a axis than along the b and c axes. From the calculated elastic constants, the mechanical properties, such as bulk modulus, shear modulus, Young's modulus, and Poisson's ratio are obtained. The calculated Raman active optical phonon frequencies and their pressure variations are in excellent agreement with available experimental results.