HSE06方法研究CaB_6电子结构、成键特性以及理论光学性质  

Electronic Structure,Bonds and Optical Properties of CaB_6 Calculated Using the HSE06 Method

作　　者：徐娟娟[1] 陈晨[2] 杨洪军[1] XU Juan-juan;CHEN Chen;YANG Hong-jun(Manzhouli College, Inner Mongolia University, Manzhouli 021400, China;College of Instrumentation ＆ Electrical Engineering, Jilin University, Changchun 130061, China)

机构地区：[1]内蒙古大学满洲里学院,内蒙古满洲里021400 [2]吉林大学仪器科学与电子科学工程学院,吉林长春130061

出　　处：《中北大学学报（自然科学版）》2018年第2期225-229,共5页Journal of North University of China(Natural Science Edition)

基　　金：内蒙古自治区高等学校科学研究资助项目(NJZY16558)

摘　　要：采用第一性原理的HSE06杂化泛函方法计算了CaB_6的电子结构、成键特性及理论光学性质,并与广义梯度近似法(GGA)的计算结果进行了对比.计算结果表明,CaB_6是一个带隙为0.745eV的直接带隙半导体,HSE06方法计算结果与实验结果吻合得更好.其费米面附近的价带和导带主要来自于B的2p态电子和Ca的3d态电子的贡献.Mulliken电荷布局分析表明,采用GGA-PBE和HSE06方法计算得到从Ca到B的电荷转移分别为1.74e和1.87e,说明CaB_6中离子键和共价键共存.采用HSE06方法计算得到的介电函数虚部的峰比GGA-PBE方法得到的峰位于更高能量处,这与HSE06方法中能带变宽有关.The first-principles hybrid density function theory with the HSE06 method was used to calculate the electronic structure,bonds and optical properties of CaB6,and the results were compared with the results from GGA-PBE method.The calculations show that CaB6 is a kind of direct semiconductor with a HSE06 band gap of 0.745 eV,which is consistent well with the experimental results.The valence bands and conduction bands near Fermi surface are composed of B 2 pand Ca 3 dstates,respectively.The Mulliken population analysis show that the charge transfer from Ca to B are 1.74 e calculated by the GGA-PBE and 1.87 e calculated by the HSE06 method.Respectively,indicating that covalent nature and ionic nature both exists in CaB6.The peaks in imaginary parts of the dielectric function from the HSE06 method are located at higher energy position than that of GGA-PBE method,which is relevant to the broadened energy gap in the HSE06 method.

关 键 词：CaB6 第一性原理 电子结构 HSE06方法 

分 类 号：O469[理学—凝聚态物理]