基于氧化锌原胞的晶格优化方法研究  

Research on Lattice Optimization Methods Based on ZnO Primitive Cell

作　　者：牙莉荀 黄宝丹 劳妃玲 许钟华 房慧 陈春燕 YA Lixun;HUANG Baodan;LAO Feiling;XU Zhonghua;FANG Hui;CHEN Chunyan(College of Physics and Electronic Engineering,Guangxi Normal University for Nationalities,Chongzuo,Guangxi,532200,China)

机构地区：[1]广西民族师范学院物理与电子工程学院,广西崇左532200

出　　处：《广西科学》2021年第2期181-188,共8页Guangxi Sciences

基　　金：广西高校中青年教师科研基础能力提升项目(2020KY20013);广西民族师范学院科学研究人才启动项目(2019BS002);中国大学生创新创业训练计划项目(201910604066)资助。

摘　　要：以氧化锌原胞的晶格优化为例,比较VASP计算程序包中2种晶格优化方法的差异:一种是状态方程拟合法,先设置参数ISIF=2,保持晶格体积不变,优化离子位置,对体积进行缩放计算得到能量与体积之间的关系图(E V关系图),然后通过Brich Murnaphan状态方程(BM状态方程)拟合E V图得到平衡体积,最后通过平衡体积重新计算得到晶格参数;另一种是自动优化法,直接设置参数ISIF=3,同时优化晶格体积和离子位置,计算完毕直接读取晶格参数。结果表明:对于氧化锌原胞而言,2种优化方法得到的晶格体积、晶格常数a、b、c的误差为0.28%、0.11%、0.11%、0.06%;在不同的初始晶格体积条件下,自动优化法得到的晶格体积、晶格常数a、b、c的误差为0.20%-0.77%、0.04%-0.55%、0.04%-0.55%、0.02%-0.63%。与实验参考值相比,2种优化方法得到的晶格常数误差不超过2%,晶体体积误差不超过4%,属于合理的误差范围。综上可知,对于类似氧化锌原胞的简单晶格体系,直接采用ISIF=3自动优化即可得到较为准确的晶格参数结果。Taking the lattice optimization of ZnO primitive cell as an example,the differences of two lattice optimization approaches in VASP package are compared.One approach is the state equation fitted method.Firstly,the parameter ISIF=2 is set to keep the lattice volume unchanged,the ion position is optimized,and the volume is performed scaling calculation to obtain the E V diagram.Then,the equilibrium volume is obtained by fitting the E V diagram with the Brich Murnaphan equation.Finally,the lattice parameters are recalculated by the equilibrium volume.The other approach is the auto optimization method.The parameter ISIF=3 is set directly,the lattice volume and ion position are optimized,and the lattice parameters are read directly after calculation.For ZnO primitive cell,the results show that the error of lattice volume,lattice constants a,b,and c obtained by the two optimization methods is 0.28%,0.11%,0.11%,and 0.06%,respectively.Under different initial lattice volume conditions,the error range of lattice volume,lattice constants a,b and c obtained by auto optimization method is 0.20%-0.77%,0.04%-0.55%,0.04%-0.55%,0.02%-0.63%.Compared with the experimental reference value,the error of lattice constant obtained by the two optimization methods is not more than 2%,and the error of crystal volume is not more than 4%,which belong to a reasonable error range.In summary,for the simple lattice system similar to ZnO primitive cell,the accurate lattice parameters can be obtained by directly using ISIF=3 auto optimization.

关 键 词：第一性原理 氧化锌 晶格优化 BM方程拟合 VASP 

分 类 号：X123[环境科学与工程—环境科学]