标题： 混合密度泛函对相变存储材料电子和光学性质的研究：$\mathrm{Ge_{2}Sb_{2}Te_{5}}$ 显示英文标题

标题： Hybrid density functional study of electronic and optical properties of phase change memory material: $\mathrm{Ge_{2}Sb_{2}Te_{5}}$

摘要： 在本文中，我们使用混合密度泛函（HSE06）研究了著名相变存储材料$\mathrm{Ge_{2}Sb_{2}Te_{5}}$的晶体和电子结构以及光学性质。我们计算了该材料三种稳定结构的结构参数、带隙和介电函数。我们还利用Bader电荷分析理论分析了电子电荷分布。我们发现混合密度泛函略微高估了'C'参数的值。然而，总体而言，使用混合密度泛函（HSE06）计算的结果比使用PBE泛函计算的结果更接近现有的实验值。具体来说，该材料使用HSE06计算的电子带隙值与文献中现有的实验数据有很好的一致性。此外，我们进行了电荷分析，发现简单的离子模型无法解释组成原子之间的电荷分布，表明了该化合物的复杂性。 显示英文摘要

摘要： In this article, we use hybrid density functional (HSE06) to study the crystal and electronic structures and optical properties of well known phase change memory material $\mathrm{Ge_{2}Sb_{2}Te_{5}}$. We calculate the structural parameters, band gaps and dielectric functions of three stable structures of this material. We also analyze the electron charge distribution using the Bader's theory of charge analysis. We find that hybrid density functional slightly overestimate the value of 'C' parameter. However, overall, our results calculated with the use of hybrid density functional (HSE06) are very close to available experimental values than calculated with the use of PBE functional. Specifically, the electronic band gap values of this material calculated with HSE06 are in good agreement with the available experimental data in the literature. Furthermore, we perform the charge analysis and find that naive ionic model fails to explain the charge distribution between the constituent atoms, showing the complex nature of this compound.