Excitonic Effects in the Optical Spectra of Lithium metasilicate (Li2SiO3)

TL;DR

This paper uses ab-initio simulations to explore excitonic effects and optical properties of Li2SiO3, revealing strong excitonic influences, polarization behaviors, and detailed optical excitation structures relevant for battery materials.

Contribution

It provides a comprehensive ab-initio analysis of excitonic effects and optical responses in Li2SiO3, advancing understanding of its electronic and optical properties for battery applications.

Findings

Large redshift of optical onset frequency due to excitonic effects

Identification of polarization-dependent optical responses

Detailed mapping of 22 optical excitation structures

Abstract

The Li2SiO3 compound, a ternary electrolyte compound of Lithium-ion based batteries, exhibits unique geometric and band structures, an atom-dominated energy spectrum, charge densities distributions, atom and orbital-projected density of states, and strong optical responses. The state-of-the-art analysis, based on an ab-initio simulation, have successfully confirmed the concise physical/chemical picture and the orbital bonding in Li-O and Si-O bonds. Additionally, the unusual optical response behavior includes a large redshift of the onset frequency due to the extremely strong excitonic effect, the polarization of optical properties along three-directions, 22 optical excitations structures and the most prominent plasmon mode in terms of the dielectric functions, energy loss functions, absorption coefficients, and reflectance spectra. The close connections of electronic and optical properties can identify a specific orbital hybridization for each distinct excitation channel. The developed theoretical framework will be very appropriate for fully comprehending the diverse phenomena of cathode/electrolyte/anode materials in ion-based batteries.