Optical response and band structure of LiCoO2 including electron-hole interaction effects

Abstract

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.

12 pages, 10 figures

References in corpus (2)

• Quasiparticle self-consistent $GW$ method; a basis for the independent-particle approximation
• Band convergence and linearization error correction of all-electron GW calculations: The extreme case of zinc oxide

Cited by in corpus (2)

• Theoretical methods for excitonic physics in two-dimensional materials
• Improved quasiparticle self-consistent electronic band structure and excitons in $\beta$-LiGaO${}_2$