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Electro-optical and phonon properties of PbTiO3/CaTiO3/SrTiO3 ferroelectric superlattices: a first-principles calculation
Journal of Nanophotonics ( IF 1.5 ) Pub Date : 2021-05-01 , DOI: 10.1117/1.jnp.15.026003 Fariba Ahmadi 1 , Houshang Araghi 1
Journal of Nanophotonics ( IF 1.5 ) Pub Date : 2021-05-01 , DOI: 10.1117/1.jnp.15.026003 Fariba Ahmadi 1 , Houshang Araghi 1
Affiliation
We studied the electronic structure as well as the dielectric, optical, and phonon properties of PbTiO3 / CaTiO3 / SrTiO3 ferroelectric superlattices, based on the density functional theory, using the Perdew–Becke–Johnson-generalized gradient approximation exchange-correlation functional. According to the results, the superlattice under investigation possessed a semiconducting phase with an indirect band gap of 1.84 eV. The results obtained for the partial density of states were indicative of a strong hybridization between the Ti-3d and O-2p states, which affected the amplitude of the Coulomb interaction and ferroelectric property. Regarding the optical properties, we calculated and analyzed the dielectric function and, accordingly, the refractive index, reflectivity, absorption coefficient, energy loss function, and optical conductivity. Thermal vibrations of the lattice were calculated along the high-symmetry path of the first Brillouin zone. Phonon dispersion data revealed stability at point Γ, while ferroelectric and dielectric responses of superlattice could be in unstable modes at other points of the Brillouin zone. Our results comprehensively present the electronic structure, dielectric function, plasmonic features, and dynamical stability based on phonon calculations, which are all essential for novel functional device applications.
中文翻译:
PbTiO 3 / CaTiO 3 / SrTiO 3铁电超晶格的电光和声子性质:第一性原理计算
基于密度泛函理论,我们使用Perdew-Becke-Johnson-广义梯度近似交换-相关函数,研究了PbTiO3 / CaTiO3 / SrTiO3铁电超晶格的电子结构以及介电,光学和声子性质。根据结果,所研究的超晶格具有半导体相,其间接带隙为1.84 eV。对于部分态密度获得的结果表明,Ti-3d和O-2p态之间发生了强烈的杂化,从而影响了库仑相互作用的幅度和铁电性能。关于光学性能,我们计算并分析了介电函数,并因此计算并分析了折射率,反射率,吸收系数,能量损失函数和光导率。沿着第一布里渊区的高对称路径计算出晶格的热振动。声子色散数据显示出在点Γ处的稳定性,而超晶格的铁电和介电响应在布里渊区的其他点可能处于不稳定模式。我们的结果基于声子计算全面展示了电子结构,介电功能,等离激元特征和动态稳定性,这些对于新颖的功能器件应用都是必不可少的。
更新日期:2021-05-12
中文翻译:
PbTiO 3 / CaTiO 3 / SrTiO 3铁电超晶格的电光和声子性质:第一性原理计算
基于密度泛函理论,我们使用Perdew-Becke-Johnson-广义梯度近似交换-相关函数,研究了PbTiO3 / CaTiO3 / SrTiO3铁电超晶格的电子结构以及介电,光学和声子性质。根据结果,所研究的超晶格具有半导体相,其间接带隙为1.84 eV。对于部分态密度获得的结果表明,Ti-3d和O-2p态之间发生了强烈的杂化,从而影响了库仑相互作用的幅度和铁电性能。关于光学性能,我们计算并分析了介电函数,并因此计算并分析了折射率,反射率,吸收系数,能量损失函数和光导率。沿着第一布里渊区的高对称路径计算出晶格的热振动。声子色散数据显示出在点Γ处的稳定性,而超晶格的铁电和介电响应在布里渊区的其他点可能处于不稳定模式。我们的结果基于声子计算全面展示了电子结构,介电功能,等离激元特征和动态稳定性,这些对于新颖的功能器件应用都是必不可少的。