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arXiv · 2106.09137

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

Santosh Kumar Radha·Walter R. L. Lambrecht·Brian Cunningham·Myrta Grüning·Dimitar Pashov·Mark van Schilfgaarde
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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.

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Santosh Kumar Radha, Walter R. L. Lambrecht, Brian Cunningham, Myrta Grüning, Dimitar Pashov, Mark van Schilfgaarde. 2021-06-16. Optical response and band structure of LiCoO2 including electron-hole interaction effects. https://doi.org/10.1103/physrevb.104.115120

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