镧系氮化物弹性性质与光学性质的第一性原理计算  

First-Principles Calculations of Elastic and Optical Properties of LnN

作　　者：杨晓翠[1] 赵衍辉[1] 刘芳[1] 罗香怡[1] 肖俊平[2] 

机构地区：[1]白城师范学院物理学院,吉林白城137000 [2]吉林大学超硬材料国家重点实验室,长春130012

出　　处：《吉林大学学报（理学版）》2013年第5期937-940,共4页Journal of Jilin University:Science Edition

基　　金：吉林省教育厅"十一五"科学技术研究项目(批准号:2010217);白城师范学院重点科研项目(批准号:201301)

摘　　要：采用基于密度泛函的第一性原理方法,计算镧系氮化物的弹性性质、光学性质和Debye温度.计算结果表明:轻镧系元素(Ln=La,Ce,Pr,Nd,Pm,Sm,Eu)氮化物(除LaN外)的体弹模量B与剪切模量G的比值均大于1.75;重镧系金属元素(Ln=Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu)氮化物(除GdN外)的B/G均小于1.75;HoN晶体具有较高的介电常数和光学反射率;LaN晶体具有较高的折射率;镧系氮化物的Debye温度为300-500 K,即声子振动频率的数量级为1013s-1.The elastic, optical properties and Debye temperature of LnN were investigated by means of first-principles calculations based on density functional theory. The calculated elastic constants show that the B/G ratio of light LnN （Ln=La,Ce,Pr,Nd,Pm,Sm,Eu） is larger than 1.75 except LaN, indicating that these crystals are ductile, while the ratio of heavy LnN （Ln=Gd,Tb,Dy, Ho,Er,Tm, Yb,Lu） is smaller than 1.75 except GdN, indicating that these crystals are brittle. The optical property shows that the static dielectric constant and reflection coefficient of HoN are the highest among those of all the LnN compounds, and shows that refractive index of LaN is the highest among those of all the LnN compounds. The Debye temperature of LnN is between 300--500 K, indicating that the order of magnitude of the phonon vibration is 10^13 s-1.

关 键 词：第一性原理计算 弹性性质 光学性质 Debye温度 

分 类 号：O482.1[理学—固体物理]