高压下BaHfO3电子结构与光学性质的第一性原理研究

从第一性原理出发,在局域密度近似下,采用基于密度泛函理论的平面波超软赝势计算方法系统地研究了高压对BaHfO₃电子结构与光学性质的影响.能带结构分析表明;无压强和施加正压强作用时,BaHfO₃为直接带隙绝缘体,而施加负压强时,BaHfO₃则转变为间接带隙半导体;BaHfO₃的带隙随压强增加而减小,且具有明显的非线性关系.对光学性质的分析发现:施加正压强后,光学吸收带边产生蓝移;负压强作用时介电函数虚部尖峰减少,光学吸收带边产生红移;施加压强后BaHfO₃的静态介电常数和静态折射率均增大.上述研究表明施加高压有效调制了BaHfO₃的电子结构和光学性质,计算结果为BaHfO₃光电材料的设计与应用提供了理论依据.

First-principles study on the electronic structures and optical properties of BaHfO3 under high pressure

The cubic perovskite-type BaHfO3 has been investigated by the first-principles plane-wave pseudo-potential method based on the density function theory. The electronic structure and optical properties of BaHfO3 are calculated under high pressure. The band structure analysis indicates that BaHfO3 is a direct-band-gap insulator in the case of without pressure and imposing positive pressure, while BaHfO3 is transformed into an indirect-band-gap semiconductor under negative pressure. Besides, the band gap of BaHfO3 decreases with an increase of pressure, and it appears obvious nonlinear relationship. The optical properties calculations show that the absorption edge is blue-shifted when imposing positive pressure, while the absorption edge is red-shifted and peaks of imaginary part of the dielectric function are decreased when imposing negative pressure. Furthermore, the static dielectric constant and static refractive index of BaHfO3 under high pressure are increased. In a word, the involved results have shown that the high pressure effectively modulates the electronic structure and optical properties of BaHfO3, which will provide a theoretical basis for the design and application of BaHfO3 optoelectronic materials.