Boucenna S, Haddadi K, Bouhemadou A, Louail L, Soyalp F, Khenata R
Unité de Recherche Matériaux Emergents, University Ferhat Abbas Setif 1, 19000, Setif, Algeria.
Unité de Recherche Matériaux Emergents, University Ferhat Abbas Setif 1, 19000, Setif, Algeria.
J Mol Graph Model. 2019 Nov;92:74-85. doi: 10.1016/j.jmgm.2019.07.006. Epub 2019 Jul 17.
In order to shed light on the unexplored properties of the ternary nitride CaTiN, we report for the first time the results of an ab initio study of its structural, electronic, elastic, chemical bonding and thermodynamic properties. Calculated equilibrium structural parameters are in excellent concordance with available experimental data. Electronic properties were explored through the calculation of the energy band dispersions and density of states. It is found that CaTiN has an indirect band gap (Z-Γ) of 1.625 (1.701) eV using LDA (GGA). Nature of the chemical bonding was studied via Mulliken population analysis and charge density distribution map. It is found that the Ca-N bond is dominantly ionic, whereas the Ti-N one is dominantly covalent. Elastic properties of both single-crystal and polycrystalline phases of the title compound were explored in details using the stain-stress approach. Analysis of the calculated elastic moduli reveals that the title compound is mechanically stable, ductile and elastically anisotropic. Temperature and pressure dependencies of the unit-cell volume, bulk modulus, heat capacities, volume thermal expansion coefficient, Grüneisen parameter and Debye temperature were investigated based on the quasiharmonic Debye model.
为了深入了解三元氮化物CaTiN尚未被探索的性质，我们首次报告了对其结构、电子、弹性、化学键和热力学性质的第一性原理研究结果。计算得到的平衡结构参数与现有的实验数据高度一致。通过计算能带色散和态密度来探索电子性质。结果发现，使用LDA（广义梯度近似）时，CaTiN的间接带隙（Z-Γ）为1.625（1.701）电子伏特。通过Mulliken布居分析和电荷密度分布图研究了化学键的性质。结果发现，Ca-N键主要是离子键，而Ti-N键主要是共价键。使用应变-应力方法详细研究了标题化合物单晶和多晶相的弹性性质。对计算得到的弹性模量的分析表明，标题化合物在力学上是稳定的、有延展性的且具有弹性各向异性。基于准谐德拜模型研究了晶胞体积、体模量、热容、体积热膨胀系数、格林爱森参数和德拜温度与温度和压力的关系。
