Exploring pressure induced thermoelectric properties of LiAeH3 (Ae = Ca, Sr, Ba) perovskite hydrides along with optoelectronic features

Abstract

This report aims to demonstrate the plane wave pseudopotential approached ab initio computation based on density functional method integrated within semi-classical Boltzmann transport theory to investigate the pressure induced electronic, optical and thermoelectric properties of LiAeH3 (Ae = Ca, Sr, Ba) perovskite hydrides. The computed electronic structures of these compounds possess indirect band gaps with mixed covalent and ionic bonding in the whole range of studied pressure (0–50 GPa) in which the band gaps of LiCaH3 decrease while those of LiSrH3 and LiBaH3 increase as the pressure increases. The rational analyses of optical spectra devote these perovskites to optoelectronic applications. For instance, the investigated hydrides reveal plasmonic excitation owing to their unique loss spectra, which are significant in optical sensing devices. The estimated electronic and optical parameters are compared, whenever possible, to the available results and found a reasonable agreement among them. To further assess physical behavior, the pressure and temperature dependent thermoelectric properties in terms of Seebeck coefficients, thermal conductivities, electrical conductivities, power factors and figure of merits are carried out first time as implemented in the BoltzTraP code. The estimated positive Seebeck coefficients of the studied perovskites exhibit p-type semiconducting nature, and thus holes are the majority charge carriers for conduction rather than electrons. The large figure of merits and small thermal to electrical conductivity ratios disclose their suitability in thermoelectric device applications.