LiBX_2(B=Ga,In;X=S,Se,Te)光学性质与力学性质的第一性原理计算  

First-principles calculations of optical and mechanical properties of LiBX_2(B = Ga,In;X =S,Se,Te)

作　　者：马天慧[1] 庄志萍[1] 任玉兰[1] 

机构地区：[1]牡丹江师范学院化学化工学院,牡丹江157012

出　　处：《物理学报》2012年第19期409-415,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50902027);黑龙江省教育厅青年学术骨干项目(批准号:1252G061);牡丹江师范学院青年学术骨干基金(批准号:G201002)资助的课题~~

摘　　要：采用基于第一性原理的赝势平面波方法系统地计算了LiBX_2(B=Ga,In;X=S,Se,Te)晶体的光学性质与力学性质.由禁带宽度推断出晶体抗激光损伤阈值的大小顺序为LiGaS2>LiInS2>LiGaSe2>LiInSe2>LiGaTe2>LiInTe_2.六种晶体在常压下均满足机械力学稳定性要求,且铟化合物可塑性及延展性强于镓化合物.这些晶体的静态电介电常数ε1(0)、静态折射率n(0)和双折射率△n理论计算值与实验值相符.LiGaS_2,LiInS_2,LiGaSe_2,LiInSe_2和LiGaTe_2五种化合物双折射率较高,并且它们的吸收谱与反射谱在中远红外区是透过的,因此可推断出这五种化合物可以成为优异的中远红外非线性光学材料.First-principles calculations of optical and mechanical properties of LiBX2 （B = Ga,In; X = S,Se,Te） are performed using plane-wave pseudopotential method. According to the order of band gaps, the order of laser induced damage thresholds is LiGaS2 〉 LiInS2 〉 LiGaSe2 〉 LiInSe2 〉 LiGaTe2 〉 LiInTe2. The elastic constants of these crystals can all meet the mechanical stability conditions at normal pressure, and the plasticitics and ductilities of indium compounds are better than those of gallium compounds. Theoretical values of average static electronic dielectric constant e 1（0）, average ordinary refraction index no and birefringence index An of these crystals are in good agreement with the experimental data. LiGaS2, LiInS2, LiGaSe2, LiInSe2 and LiGaTe2 compounds have the large birefringences and their absorption and reflectivity spectra are transmissible through mid- and far-IR region, so the five crystals are likely to be promising materials for nonlinear optical applications in the mid- and far-IR region.

关 键 词：弹性常数 介电常数 双折射率 正交结构 

分 类 号：O469[理学—凝聚态物理]