密度泛函理论研究MgH_2的电子和光学性质  

Density Functional Theory Study on Electronic and Optical Properties of MgH_2

作　　者：安辛友[1,2] 杨辉[2] 任维义[2] 贺梓淇 陈太红[2] 曾体贤[2] 

机构地区：[1]南京理工大学电光学院,南京210094 [2]西华师范大学物理与空间科学学院,南充637000

出　　处：《人工晶体学报》2017年第5期837-844,共8页Journal of Synthetic Crystals

基　　金：中科院太阳活动重点实验室开放课题(KLSA201514);四川省科技厅应用基础项目(2014JY0133)

摘　　要：基于密度泛函理论,采用平面波赝势和BFGS法计算研究了金红石相MgH_2电子结构性质和线性光学性质。基态下,金红石相MgH_2晶体具有良好的弹性力学稳定性,基本结构参数与实验值及其其他理论值符合得较好。Mulliken电荷分布和集居数分析发现:金红石相MgH_2晶体中电荷主要从Mg原子向H原子转移,电荷总数主要来源于Mg2p态电子和H1s态电子,金红石相MgH_2属于共价键和离子键混合型化合物。结合电子性质和频率相关介电函数ε(ω)计算研究了金红石相MgH_2的介电函数、线性吸收系数、复折射率及消光系数、反射率和能量损失谱,结果表明:金红石相MgH_2的主要吸收区间位于紫外光区;24.88~42.35 e V能量区间金红石相MgH_2具有很强的透过性;高频情况下,金红石相MgH_2具有极高的反射率。Based on the density functional theory, electronic and optical properties of rutile-MgH2 have been investigated using the plane-wave pseudopotential and BFGS approaches. At ground state, rutile- MgH2 crystal has good elasticity stability. The calculated equilibrium structural parameters are in excellent agreement with the experimental and other theoretical results. Mulliken population analysis of rutile-MgH2 indicates that the charge transfers are from Mg to H. The total charge is mainly derived from the Mg2p and H ls states, and rutile-MgH2 is mixture bonding material （covalent ＋ ionic bond）. Combing with the electronic properties and frequency-dependent dielectric function ε （ω）, the dielectric function, absorption coefficient, refractive index, extinction coefficient, reflectivity and loss function of rutile-MgH2 were calculated and investigated in detail. Results indicate that the main absorption ranges of rutile-MgH2 are located in ultraviolet region, rutile-MgH2 has a very strong permeability between 24.88 and 42.35 eV, and in high frequency case, it has a very high reflectivity.

关 键 词：Mg H2 密度泛函理论 电子性质 光学性质 

分 类 号：O443.5[理学—电磁学]