Orbital-hybridization-created optical excitations in Li2GeO3

TL;DR

This paper uses first-principles calculations to explore the orbital hybridizations and optical excitations in Li2GeO3, revealing unique optical properties and excitonic effects relevant for battery materials.

Contribution

It provides a detailed theoretical analysis of the orbital hybridizations and optical responses in Li2GeO3, highlighting the role of electronic structure in optical excitations.

Findings

Identification of critical orbital hybridizations in Li-O and Ge-O bonds

Observation of unusual optical transitions and plasmon modes

Strong excitonic effects influencing optical excitations

Abstract

Li2GeO3, a ternary electrolyte compound of Li+-based battery, presents the unusual essential properties. The main features are thoroughly explored from the first-principles calculations. The concise pictures, the critical orbital hybridizations in Li-O and Ge-O bonds, are clearly examined through the optimal Moire superlattice, the atom-dominated electronic energy spectrum, the spatial charge densities, the atom- and orbital-decomposed van Hove singularities, and the strong optical responses. The unusual optical transitions cover the red-shift optical gap, 16 frequency-dependent absorption structures and the most prominent plasmon mode in terms of the dielectric functions, energy loss functions, reflectance spectra, and absorption coefficients. Optical excitations, depending on the directions of electric polarization, are strongly affected by the excitonic effects. The close combinations of electronic and optical properties can identify a significant orbital hybridization for each available excitation channel. The developed theoretical framework will be very useful in fully understanding the diverse phenomena of cathode/electrolyte/anode materials in ion-based batteries.