Theoretical study of structural, electronic, lattice dynamical and dielectric properties of SrAl2O4
Theoretical study of structural, electronic, lattice dynamical and dielectric properties of SrAl2O4
复制标题
SrAl2O4结构、电子、晶格动力学和介电性能的理论研究
DOI：
10.1016/j.jallcom.2011.01.046
复制
发表时间：
2011-03-17
影响因子：
6.2
通讯作者：
Ni, Chen
中科院分区：
文献类型：
--
作者：
Liu, Bo;Gu, Mu;Ni, Chen
我们调查的结构，电子，晶格动力学，和介电性能的SrAl2O4内的密度函数理论。晶体结构是完全弛豫的，结构参数与实验数据吻合得很好。局部密度近似（LDA）和广义梯度近似（GGA）的体积弹性模量的一阶压力导数分别为2.5和4.3。电子能带结构表明，价带顶由O 2p态和少量Al 3s和3p态组成，导带底由Sr 5s态和少量O 2p、Al 3s和Al 3p态组成.利用密度函数微扰理论计算了布里渊区中心的声子频率和介电常数张量。通过LDA和GGA形式化计算，理论上预测了电子（无穷大）和静态（无穷大）介电常数张量。结果表明，电子介电常数是各向同性的，而静态介电常数由于离子对静态介电常数的贡献占主导地位而表现出一定的各向异性. (C)2011 Elsevier B.V.保留所有权利。
We investigate the structural, electronic, lattice dynamical, and dielectric properties of SrAl2O4 within density-function theory. The crystal structure is fully relaxed, and the structural parameters are found to be well consistent with the experimental data. The first pressure derivatives of the bulk modulus are predicted to be 2.5 and 4.3 for local density approximation (LDA) and generalized gradient approximation (GGA), respectively. The electronic band structure shows that the valence band maximum is comprised of O 2p states and a small amount of Al 3s and 3p states, and the conduction band minimum is comprised of Sr 5s and a small amount of O 2p, Al 3s and Al 3p states. The phonon frequencies at the center of the Brillouin zone and the dielectric permittivity tensors are calculated using density-function perturbation theory. The electronic (epsilon(infinity)) and static (epsilon(0)) dielectric permittivity tensors are theoretically predicted by the calculations with both LDA and GGA formalisms. The results show that the electronic dielectric permittivity is isotropic, while the static dielectric permittivity exhibits to be somewhat anisotropic due to the dominant ionic contributions in static dielectric permittivity. (C) 2011 Elsevier B.V. All rights reserved.