单轴压缩下固态硝基苯的第一性原理研究

发布时间：2018-02-16 22:02

本文关键词： 硝基苯单轴压缩静水压含能材料　出处：《物理学报》2017年03期 　论文类型：期刊论文

【摘要】：采用第一性原理密度泛函理论结合经典色散修正方法,对固态硝基苯在单轴压缩下的基本结构关系进行了计算.静水压缩和单轴压缩都压缩到初始平衡体积的70%.将静水压下优化后的晶胞体积、晶格参数以及平衡条件下的晶格能与实验值进行了比较,均符合较好.同时,为了充分地表征固态硝基苯的各向异性,将硝基苯沿着三个晶格矢量的方向进行单轴压缩,把每个方向的应力张量、能带带隙、每个原子能量的改变分别作为体积压缩比的函数进行了比较和分析.其中,最显著的各向异性效应是在体积压缩比为0.76时,沿X轴压缩导致硝基苯能带带隙闭合,体系呈金属化;而静水压缩或沿Y轴和Z轴压缩时体系始终呈半导体状态,带隙均大于1.59 eV.为了充分理解这一各向异性特性,我们计算了硝基苯晶体的局域态密度和电荷密度分布,并对金属化现象做出了合理的分析和解释.在不同的压力加载条件下,通过对不同物理量的计算,发现X轴方向是硝基苯晶体内部最敏感的方向.这些各向异性效应的研究将有助于人们在原子尺度上深入理解固态硝基苯的物理化学性质.
[Abstract]:The first principle density functional theory (DFT) combined with the classical dispersion correction method is used. The basic structural relationships of solid nitrobenzene under uniaxial compression are calculated. Both hydrostatic compression and uniaxial compression are compressed to 70 of the initial equilibrium volume. The unit cell volume is optimized under hydrostatic pressure. The lattice parameters and the lattice energy under equilibrium conditions are in good agreement with the experimental values. Meanwhile, in order to fully characterize the anisotropy of solid nitrobenzene, the uniaxial compression of nitrobenzene along the direction of three lattice vectors is carried out. The variation of stress Zhang Liang, band gap and atomic energy in each direction is compared and analyzed as a function of volume squeezing ratio. The most significant anisotropic effect is when the volume squeezing ratio is 0.76. The band gap of nitrobenzene energy band is closed and the system is metallized by X-ray compression, while the system is always semiconductor under hydrostatic compression or compression along Y-axis and Z-axis, and the band gap is larger than 1.59 EV. In order to fully understand this anisotropic property, the band gap is larger than 1.59 EV, and the band gap is larger than 1.59 EV in order to fully understand the anisotropy. The local density of states and the distribution of charge density of nitrobenzene crystal are calculated, and the metallization phenomenon is analyzed and explained reasonably. It is found that the X axis direction is the most sensitive direction in the crystal of nitrobenzene, and the study of these anisotropic effects will be helpful to understand the physical and chemical properties of solid nitrobenzene on atomic scale.
【作者单位】：大连理工大学三束材料改性教育部重点实验室;中国工程物理研究院流体物理研究所冲击波与爆轰物理国家实验室;
【基金】：国防基础科研核基础科学挑战计划(批准号:JCKY2016212A501) 国家自然科学基金(批准号:11674046) 中国博士后科学基金(批准号:2016M592704) 大连理工大学超算中心资助的课题~~
【分类号】：TB34

【相似文献】