第一性原理研究α-Al_2O_3的电子结构、力学性质和德拜温度  

First Principle Study of Electronic Structures,Mechanical Properties and Debye Temperature of α-Al_2O_3

作　　者：燕云程 YAN Yuncheng(School of Materials Science and Engineering, Baise University, Baise 53300)

机构地区：[1]百色学院材料科学与工程学院,百色533000

出　　处：《材料导报》2018年第A01期512-516,共5页Materials Reports

摘　　要：采用基于密度泛函理论的平面波超软赝势的第一性原理方法,利用CASTEP软件计算了α-Al_2O_3的电子结构、力学性质和德拜温度。计算结果显示优化后的晶格常数与实验数据基本一致。能带结构图表明α-Al_2O_3具有典型的离子化合物特征,禁带宽度为5.964eV。计算的态密度表明α-Al_2O_3的下价带在-19.426^-15.370eV之间,态密度主要由O的2s轨道电子贡献;上价带在-7.178~0.711eV之间,态密度主要由O的2p轨道电子贡献;导带在5.698~14.977eV之间,态密度主要由Al的3s和3p轨道电子贡献。差分电荷密度分布表明α-Al_2O_3中存在离子键和共价键。力学性质的计算结果表明α-Al_2O_3的体积模量为224.885GPa,剪切模量为144.687GPa,弹性模量为357.411GPa,泊松比为0.235,各向异性指数为0.220;α-Al_2O_3剪切模量与体积模量的比值为0.643,表明α-Al_2O_3具有脆性。α-Al_2O_3的德拜温度为974.834K。Electronic structures,mechanical properties and Debye temperature ofα-Al2O3 were investigated by means of first principle calculations from CASTEP program based on density functional theory（DFT）.The optimized lattice parameters are in substantial agreement with the experimental data.The energy band structure diagram shows thatα-Al2O3 has typical ionic compound characteristics,and the band gap is 5.964 eV.The calculated density of states results indicate that the lower valence band ofα-Al2O3 ranges from-19.426 eV to-15.370 eV,and the corresponding density of states is mainly contributed by 2 selectrons of oxygen atom.The upper valence band ofα-Al2O3 changes from-7.178 eV to 0.711 eV,and the corresponding density of states is mainly from 2 p electrons of oxygen atom.The conduction band is between 5.698 eV and 14.977 eV,and the corresponding density of states is mainly given by 3 sand 3 p of aluminum atom.The charge density difference shows that ionic bond and covalent bond exist inα-Al2O3.The mechanical properties were calculated,and the results indicate that the bulk modulus ofα-Al2O3 is 224.885 GPa,the shear modulus is 144.687 GPa,the elastic modulus is 357.411 GPa,Poisson＇s ratio is 0.235,and the anisotropy index is 0.220.The ratio of shear modulus to bulk modulus is equal to 0.643,which suggests thatα-Al2O3 exhibits brittleness.Debye temperature ofα-Al2O3 was calculated and the value is 974.834 K.

关 键 词：Α-AL2O3 电子结构 力学性质 德拜温度 

分 类 号：O141.4[理学—数学]