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

Research output: Contribution to journalArticlepeer-review

18 Scopus Citations

Abstract

The optical response functions and band structures of LiCoO2 are studied at different levels of approximation, from density functional theory (DFT) in the generalized gradient approximation (GGA) to quasiparticle self-consistent QSGW (with G for Green's function and W for screened Coulomb interaction) without and with ladder diagrams (QSGŴ) and the Bethe Salpeter Equation (BSE) approach. The QSGW 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.

Original languageAmerican English
Article number115120
Number of pages10
JournalPhysical Review B
Volume104
Issue number11
DOIs
StatePublished - 15 Sep 2021

Bibliographical note

Publisher Copyright:
© 2021 American Physical Society.

NREL Publication Number

  • NREL/JA-5F00-80986

Keywords

  • Bethe Salpeter Equation
  • Coulomb interaction
  • density functional theory (DFT)
  • electron-hole
  • excitonic
  • generalized gradient approximation (GGA)
  • Green's function
  • ladder diagrams
  • LiCoO2
  • QSGW^
  • quasiparticle gap
  • quasiparticle self-consistent QSGW

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