α和β-Si_(3)N_(4)的电子、光学及热力学性质的第一性原理计算  

First-principles calculationsof the electronic,optical and thermodynamic properties ofα-Si_(3)N_(4)andβ-Si_(3)N_(4)

作　　者：蒋文龙 戴涛 张帆[1] 张雨林 刘正堂[2] 杜艺华 刘其军[1] JIANG Wen-Long;DAI Tao;ZHANG Fan;ZHANG Yu-Lin;LIU Zheng-Tang;DU Yi-Hua;LIU Qi-Jun(Bond and Band Engineering Group,Southwest Jiaotong University,Chengdu 610031,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China)

机构地区：[1]西南交通大学键带工程组,成都610031 [2]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《原子与分子物理学报》2023年第2期173-180,共8页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(12147208);2021年国家级大学生创新创业训练计划项目(202110613086)。

摘　　要：基于密度泛函理论的第一性原理方法,计算了α-Si_(3)N_(4)和β-Si_(3)N_(4)的晶体结构、电子结构、光学性质和声子谱,并对结果进行了理论分析.计算结果表明两种相都含有较强的共价键,均为绝缘体,且α-Si_(3)N_(4)的禁带宽度略大于β-Si_(3)N_(4).计算获得的光学吸收系数表明α-Si_(3)N_(4)和β-Si_(3)N_(4)主要吸收紫外光,并二者的能量损失峰在24.4 eV附近.α-Si_(3)N_(4)和β-Si_(3)N_(4)的声子谱中均无虚频,表明二者的结构是稳定的.在0~1000 K范围内,α-Si_(3)N_(4)的热容约为β-Si_(3)N_(4)的两倍.本文的计算结果可以为Si_(3)N_(4)的相关应用提供理论依据.We used the first-principles method based on density functional theory to calculate the crystal structures,electronic structures,optical properties and phonon spectra ofα-Si_(3)N_(4) and β-Si_(3)N_(4).The obtained results have been theoretically analyzed.The calculated results show that both phases contain strong covalent bonds and are insulators.The band gap of α-Si_(3)N_(4) is slightly larger than that of β-Si_(3)N_(4).The calculated optical absorption coefficients show that α-Si_(3)N_(4) and β-Si_(3)N_(4) mainly absorb ultraviolet light,and their energy loss peaks are around 24.4 eV.In the phonon spectra,α-Si_(3)N_(4) and β-Si_(3)N_(4) have no imaginary frequency,indicating that they are stable.In the range of 0~1000 K,the heat capacity ofα-Si_(3)N_(4) is about twice that of β-Si_(3)N_(4).The calculated results in this paper will provide a theoretical basis for the related applications of Si_(3)N_(4).

关 键 词：氮化硅 电子结构 光学性质 声子谱 

分 类 号：O469[理学—凝聚态物理]