MnHg(SCN)_4晶体的能带结构和非线性光学性质的研究  

Study of Energy Band Structure and Nonlinear Optical Properties of MnHg(SCN)_4 Crystals

作　　者：张鹏[1] 卢贵武[1] 孔垂岗[1] 郑超[1] 宋庆翔 冯金波[1] 王新强[2] 

机构地区：[1]中国石油大学(北京)理学院,北京102249 [2]山东大学晶体材料研究所晶体材料国家重点实验室,济南250100

出　　处：《硅酸盐通报》2014年第7期1715-1719,共5页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51372140);中国石油大学(北京)基础学科研究基金(01JB0169)

摘　　要：用密度泛函微扰理论(DFPT)和GW近似方法计算了MnHg(SCN)4(MMTC)晶体的几何结构、能带结构和二阶非线性光学系数。计算得到MMTC晶体的禁带宽度为3.21 eV,结果接近实验值3.33 eV,其二阶非线性系数为d14=3.09 pm/V、d15=6.02 pm/V。结果表明Mn-3d、Hg-5d态是价带的主要成分,C-2p、N-2p和S-3p态是价带顶和导带底的主要成分,而阴离子基团(SCN)-内部的电子跃迁是MnHg(SCN)4晶体中二阶非线性效应的主要来源。The geometry structure, electronic structure and optical properties of MnHg （SCN） 4 （ MMTC ） crystal were calculated by using density functional perturbation theory （DFPT） and Green function screening interaction （GW） approximation. The band gap of MMTC is calculated to be 3.21 eV, which is in good agreement with the experimental 3.33 eV. The calculated result of the second-order nonlinear coefficients of MMTC are d14 = 3.09 pm/V and di5 = 6.02 pm/V. Moreover, we have found that the contribution to the valence band mainly comes from Mn-3d,Hg-5d states, and the contributions to the valence band bottom and the conduction band top predominantly come from C-2p, N-2p and S-3p states. It was found that the second-order nonlinear effects of MnHg （SCN）4 crystal result mainly from the internal electronic transition of （SCN） - anionic group.

关 键 词：MMTC晶体 非线性光学性质 禁带宽度 GW近似 密度泛函微扰理论 

分 类 号：O734[理学—晶体学]