hcp-,fcc-和bcc-Sc晶格稳定性的第一原理研究  

Study on lattice stability in first principles of hcp-,fcc- and bcc-Sc

作　　者：陶辉锦[1,2,3] 刘玲[1] 陈伟民[2] 文杰斌[1] 杨巧然[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学冶金科学与工程学院,长沙410083 [3]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2009年第5期299-305,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：教育部博士点新教师基金资助项目(20070533118);国家自然科学基金资助项目(50471058;50271085);中南大学博士后基金资助项目

摘　　要：分别采用第一原理总能赝势平面波的局域密度近似LDA(Localdensityapproximation)和广义梯度近似GGA(Generalizedgradientapproximation)两种近似方法计算hcp-,fcc-和bcc-Sc的晶格常数、总能和态密度,并将实验值与以上两种方法以及CALPHAD方法的计算结果进行对比研究,发现采用LDA和GGA的计算结果均为ΔGbcc-hcp>ΔGfcc-hcp>0,与CALPHAD方法外推的结果ΔGfcc-hcp>ΔGbcc-hcp>0不一致。用LDA方法计算的hcp-,fcc-和bcc-Sc的晶格常数和原子体积较GGA方法的计算结果小,但总能绝对值偏大。LDA方法与GGA方法的态密度曲线形状基本一致,但LDA得到的s和p态电子占据数比GGA方法的偏小。The local density approximation（LDA） and general gradient approximation（GGA） of total energy plane wave pseudopotential method in first principles have been used to calculate the lattice constants, total energies and density of state of hcp-, fcc- and bcc-Sc. The results have been compared with both calculated results of CALPHAD method and experimental data. It is found that lattice stability parameters obtained by LDA and GGA in first principles are all ΔGbcc-hcp〉ΔGfcc-hcp〉0 but very different with the result of CALPHAD method as △G^fcc-hcp 〉 △G^bcc-hcp 〉 0. And the lattice constants and atomic volumes calculated in LDA are smaller than those in GGA. The absolute values of total energies in LDA are larger than those in GGA. The curve shape of state density in LDA is very similar with that in GGA. But, the electronic occupation number of hcp-, fcc- and bcc-Sc in s and p state calculated in LDA are less than that in GGA.

关 键 词：SC 晶格稳定性 第一原理总能平面波赝势 LDA GGA 

分 类 号：TG111[金属学及工艺—物理冶金]