六方HfB_2弹性性质、电子结构和光学性质的第一性原理计算

采用基于密度泛函理论(DFT)框架下广义梯度近似平面波超软赝势法,计算了六方HfB2的几何结构、弹性性质、电子结构和光学性质.计算得到的晶格常数和弹性常数均与实验值相符,并说明了六方HfB2的晶体结构是稳定的;通过Reuss-Voigt-Hill模型计算得到了六方HfB2的体积、剪切、杨氏模量及泊松比,同时获得了六方HfB2的德拜温度,计算结果都与实验值相一致;六方HfB2的电子结构表明其具有金属性和共价性;计算得到六方HfB2在(100)和(001)方向上的光学线性响应函数随光子能量的变化关系,包括复介电函数、复折射率、反射光谱、吸收光谱、损失函数和复光电导谱,计算得到其静态介电常数在(100)和(001)方向上分别为47.92和27.77,折射率分别为6.93和5.27,计算结果表明了六方HfB2在(100)和(001)方向上具有光学各向异性,这为六方HfB2的应用提供了理论参考数据.

First-principles Calculation of Elastic Properties, Electronic Structure and Optical Properties of Hexagonal HfB2

tructural parameters,elastic properties,electronic structure and optical properties of hexagonal HfB2 have been investigated using the plane waves ultrasoft pseudopotential technique based on the density functional theory（DFT）.The calculated lattice parameters and elastic constants are in good agreement with the experimental data,which show that hexagonal HfB2 is elastically stable.Its bulk modulus,shear modulus,Young＇s modulus and Poisson ratio have been obtained using Reuss-Voigt-Hill approach;and Debye temperatures have been gained,which are all consistent with the experimental data.The calculated electronic structures show the metallic and covalent bonds.The optical linear response functions of hexagonal HfB2 as a function of photon energy are obtained including the complex dielectric function,complex of refractive,reflectivity,absorption coefficients,loss function and complex conductivity function from（100） and（001） direction.The static dielectric constants are 47.92 and 27.77;the refractivity index are 6.93 and 5.27 from（100） and（001） direction.The results show that the hexagonal HfB2 show an optical anisotropy in the polarization direction（100） and（001）so as to offer a theoretical basis for the application of hexagonal HfB2.