Si掺杂正交相SrHfO_3电子结构与光学性质的第一性原理计算（英文）

First-Principles Calculations of Electronic Structure and Optical Properties of Si-doped Orthorhombic SrHfO_3

采用基于密度泛函理论的平面波超软赝势方法研究了正交相SrHfO3和以Si替换Hf方式形成的掺杂态SrHfO3的形成能,几何结构,电子结构和光学性质。负的形成能表明在由单元素形成Si掺杂态的SrHfO3的反应中,Si占居Hf位置与Sr位置两种情况在能量上是有利的,并且Si原子更加倾向于占居Hf位置。纯的SrHfO3计算得到的晶格常数与文献报道的实验值和理论值是一致的,而Si占居Hf位置后会导致SrHfO3的晶格常数减小。能带结构显示在掺入Si原子后会使带隙变小。布居分析与电荷密度图一致,说明在Hf位置掺入Si后掺杂位置附近的Hf-O键以共价键为主,Sr-O键以离子键为主。最后,对Si掺杂后SrHfO3在(100)方向上的介电常数、反射率、吸收系数、折射率进行了计算与分析。

The formation energy, the geometric structure, the electronic structure and the optical properties of pure andSi-doped orthorhombic SrHfO3 with Si substituting Hf were studied by the first-principles method using plane-wave ultra-softpseudo-potential calculation based on density functional theory. The negative formation energy results show the reactions fromsingle elements to Si-doped SrHfO3 are energetically favorable and that Si prefers entering the Hf sites rather than the Sr sites.The calculated equilibrium lattice constants of pure SrHfO3 are in good agreement with previous experimental and theoreticalresults, and the substitution of Si for Hf results in a decrease in the lattice constants. The band structure indicates the band gapdecreases after introduction of Si to Hf site. The Mulliken analysis and charge densities suggest that the Hf-O bond is mainlycovalent, and the Sr-O bond is mainly ionic in Si-doped SrHfO3. The dielectric functions, the reflectivity, the absorption coefficient, the refractive index, and the energy-loss spectrum were also calculated to get a better understanding of optical properties of Si-doped SrHfO3.