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arXiv 1612.02597cond-mat.mtrl-sci
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解决固体核心激发中的电子-空穴相关性:第一性原理的全电子多体方法

Addressing electron-hole correlation in core excitations of solids: An all-electron many-body approach from first principles

Christian Vorwerk, Caterina Cocchi, Claudia Draxl

摘要:

我们提出了一个从头计算研究的核心激发的固态材料的电子空穴相关的作用集中。多体微扰理论到令人兴奋的代码的全电子实施的框架中,我们调查三种材料的三个不同的吸收边,跨越一个广泛的能量窗口,与过渡能量之间的几百到几千电子伏特。具体地说,我们考虑从钛$K$边缘的金红石和金红石$\textrm{TiO}_2$,从铅$M_4$边缘的$\textrm{PbI}_2$,和从钙$L_{2,3}$边缘的$\textrm{CaO}$的激发。我们表明,电子-空穴吸引规则的深芯态的X射线吸收,当本地字段发挥次要作用。另一方面,局部场效应引入的激发的电子和空穴之间的交换相互作用占主导地位的激发过程从较浅的核心水平,分离的自旋轨道分裂的几个电子伏特。我们的方法产生的吸收光谱与现有的实验数据很好地吻合,并允许深入分析的结果,揭示了电子的贡献的激发,以及它们的空间分布。

英文摘要:

We present an ab initio study of core excitations of solid-state materials focussing on the role of electron-hole correlation. In the framework of an all-electron implementation of many-body perturbation theory into the exciting code, we investigate three different absorption edges of three materials, spanning a broad energy window, with transition energies between a few hundred to thousands of eV. Specifically, we consider excitations from the Ti $K$ edge in rutile and anatase $\textrm{TiO}_2$, from the Pb $M_4$ edge in $\textrm{PbI}_2$, and from the Ca $L_{2,3}$ edge in $\textrm{CaO}$. We show that the electron-hole attraction rules x-ray absorption for deep core states, when local fields play a minor role. On the other hand, the local-field effects introduced by the exchange interaction between the excited electron and the hole dominate excitation processes from shallower core levels, separated by a spin-orbit splitting of a few eV. Our approach yields absorption spectra in good agreement with available experimental data, and allows for an in-depth analysis of the results, revealing the electronic contributions to the excitations, as well as their spatial distribution.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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