高压下NbN结构和电子性质的第一性原理计算  

First-principles investigations of structure and electronic properties of niobium nitrides under pressures

作　　者：李晓凤[1] 赵阿可[1] 刘中利[1] 刘秀英[2] 

机构地区：[1]洛阳师范学院物理与电子信息学院,洛阳471022 [2]河南工业大学理学院,郑州450000

出　　处：《原子与分子物理学报》2011年第3期519-526,共8页Journal of Atomic and Molecular Physics

基　　金：洛阳师范学院青年基金项目(2010-QNJJ-003);河南省教育厅基础研究项目(2011B140013)

摘　　要：利用密度泛函理论平面波赝势方法研究了NbN五种结构,即NaCl结构(Fm-3m);CsCl结构(Pm-3m);ZB结构(F4-3m);六角δ结构(P63/mmc)and e(P-6m2)结构.本文对NbN五种结构的机械稳定性,弹性性质和高压下的电子结构等都进行了详细的研究.在NbN的五种晶体结构中,我们发现六角结构NbN要比立方结构稳定,这与实验结果相一致.我们还计算了NbN各种结构的晶格常数、体模量,弹性模量以及弹性各向异性等,结果与已有的理论和实验相吻合.同时发现在290GPa左右,NaCl结构转化为CsCl结构.为了更加深入的研究NbN的高压性能,我们研究了NbN的电子性质,结果发现NbN的不同结构具有金属性,并且在高压下原子间的杂化增强.The ground structure and elastic properties of several phases of NbN are determined based on ab-initio total-energy calculations within the framework of density functional theory. Among the five crystallographic structures that have been investigated, the hexagonal phases have been found to be more stable than the cubic ones. The calculated equilibrium structural parameters are in good agreement with the available experimental results. The elastic constants of five structures in NbN are calculated, which are in consistent with the obtained theoretical and experimental data. The corresponding elastic anisotropies are also obtained. The anisotropies of ZB-NbN, NaCl-NbN, CsCl-NbN gradually increases. For hexagonal structure, the anisotropies of ε-NbN are stronger than that of σ-NbN. The electronic structures of NbN under pressure are investigated. It is found that NbN have metallization and the hybridizations of atoms under pressure become stronger.

关 键 词：NBN 高压相变 弹性性质 电子结构 

分 类 号：O482[理学—固体物理]