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

Article

关键词: AB-INITIO CALCULATION;    DIELECTRIC-CONSTANT;    TRANSITION-METALS;    OPTICAL-SPECTRA;    GREENS-FUNCTION;    RUTILE;    SEMICONDUCTORS;    APPROXIMATION;    CRYSTAL;    ANATASE;   

DOI  :  10.1103/PhysRevB.95.155121

来源: SCIE

【 摘 要 】

We present an ab initio study of core excitations of solid-state materials focusing 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 TiO2, from the Pb M-4 edge in PbI2, and from the Ca L-2,L-3 edge in 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.

【 授权许可】

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