准粒子
激子
物理
带隙
电子能带结构
凝聚态物理
库仑
材料科学
电子
量子力学
超导电性
作者
Santosh Kumar Radha,Walter R. L. Lambrecht,B. Cunningham,Myrta Grüning,Dimitar Pashov,Mark van Schilfgaarde
出处
期刊:Physical review
日期:2021-09-09
卷期号:104 (11)
被引量:17
标识
DOI:10.1103/physrevb.104.115120
摘要
The optical response functions and band structures of LiCoO$_2$ are studied at different levels of approximation, from density functional theory (DFT) in the generalized gradient approximation (GGA) to quasiparticle self-consistent QS$GW$ (with $G$ for Green's function and $W$ for screened Coulomb interaction) without and with ladder diagrams (QS$G\hat W$) and the Bethe Salpeter Equation (BSE) approach. The QS$GW$ method is found to strongly overestimate the band gap and electron-hole or excitonic effects are found to be important. They lower the quasiparticle gap by only about 11~\% but the lowest energy peaks in absorption are found to be excitonic in nature. The contributions from different band to band transitions and the relation of excitons to band-to-band transitions are analyzed. The excitons are found to be strongly localized. A comparison to experimental data is presented.
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