Sr_2RuO_4各向异性光学性质的第一性原理研究  

Ab-initio Investigation of Anisotropic Optical Properties of Sr_2RuO_4

作　　者：蔡建秋[1,2] 陶向明[2] 罗海军[1,2] 金清理[1] 黄运米[1] 

机构地区：[1]温州大学物理与电子信息工程学院,浙江温州325035 [2]浙江大学理学院物理系,浙江杭州310027

出　　处：《光学学报》2010年第12期3580-3585,共6页Acta Optica Sinica

基　　金：浙江省教育厅科研项目(Y200804278);浙江大学中央高校基本科研业务费专项基金(2009QNA3025)资助课题

摘　　要：基于密度泛函理论的第一性原理方法研究了超导体Sr2RuO4各向异性的光学性质。考虑到温度效应对其光学性质的影响,在计算光学矩阵元时加入洛伦兹(Lorentz)展宽δ=0.20eV。计算给出了Sr2RuO4沿c方向和x方向的反射谱、光导谱及电子能量损失谱,并与实验很好地符合。由光导谱表明,Sr2RuO4的光学性质存在明显的各向异性,沿x方向的低能谱区形成了等离子体吸收峰,带内吸收和带间吸收的转换出现在1.84eV左右,而沿z方向没有出现明显的等离子体吸收。进一步分析认为主要是由于两个方向上不同的能带色散结构引起的。The anisotropic optical properties for superconductor Sr2RuO4 have been studied by full-potential linearized augmented plane wave（FLAPW） method based on density functional theory.In order to simulate the temperature effects,Lorentzian broadening（set as δ=0.20eV） is added into optical matrix elements during the calculation in these spectra.The spectra of reflectivity R（ω）,optical conductivity σ（ω） and electron energy loss have been calculated.These results consist quite well with experiments as a whole.And the optical conductivity spectrum along x-axis displays quite different features in comparison with that of z-axis.Along x-axis,σ（ω） spectrum shows an obvious Drude-like feature in low energy region while not along z-axis.The conversion between intra-band absorption and inter-band absorption appears at about 1.84 eV in the σ（ω） spectrum along x-axis.By further analysis,the anisotropy of optical properties should mainly arise from different band structure along two axes.

关 键 词：光电子学 光学性质 密度泛函 电子结构 

分 类 号：TN304.2[电子电信—物理电子学]