Elastic properties and electronic structure of tetragonal KDP crystal under polishing pressures from first principles
Elastic properties and electronic structure of tetragonal KDP crystal under polishing pressures from first principles
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DOI：
10.1142/s0217979220502860
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发表时间：
2020-12
影响因子：
1.7
通讯作者：
Huiling Jia;Feng Wang;Jinxiu Wu;X. Tan;Yanan Cao
中科院分区：
文献类型：
--
作者：
Huiling Jia;Feng Wang;Jinxiu Wu;X. Tan;Yanan Cao
采用基于密度泛函理论的平面波赝势方法，研究了抛光压力下磷酸二氢钾（KDP）的弹性性质和电子结构。结果表明，计算得到的晶格常数、弹性常数和带隙与实验结果和常压下的计算结果吻合较好。KDP的弹性常数和弹性模量随着压力的增加而增加，但KDP的维克斯硬度却随着压力的增加而降低。当压力超过3GPa时，KDP晶体由脆性向韧性转变。随着压力的增加，KDP的各向异性增大，[式：见正文]/[式：见正文]的比值增大。当压力达到4.5GPa时，四元KDP发生结构相变。随着压力的增加，O-2 [公式：见正文]和P-3 [公式：见正文]状态之间的带隙增加。在外加压力作用下，原子间距离缩短，K [式：见正文]与相邻的H2PO [式：见正文]之间的相互作用增强，导致弹性力学性能提高。
The elastic properties and electronic structure of tetragonal Potassium dihydrogen phosphate (KDP) under polishing pressures were investigated using the plane-wave pseudopotential method based on density functional theory. The results show that the calculated lattice constant, elastic constants and bandgap agreed well with the results of the experiments and the other calculations at ambient pressure. The elastic constants and the elastic moduli of KDP increase with increasing pressure, but Vickers hardness of KDP decreases. KDP crystal changes from brittleness to ductility beyond the pressure of 3 GPa. The anisotropy of KDP increases and the ratio of [Formula: see text]/[Formula: see text] increases with the increase of pressure. When the pressure reaches 4.5 GPa, the tetragonal KDP will undergo structural phase transition. As pressure increases, the bandgap between and O-2[Formula: see text] and P-3[Formula: see text] states increases. The interatomic distances were shortened under external pressure, and the interaction between K[Formula: see text] and the neighboring H2PO[Formula: see text] was enhanced, which leads to the increase of elastic mechanical properties.