Exploring the Physical Properties, Hydrogen Storage Capacity and Thermal Barrier Performance of LaMg2H7: A First-Principles Investigation

Abstract

LaMg2H7 is a ternary wide band gap semiconductor that is a member of the hydride family. The bulk physical characteristics of the LaMg2H7 compound, including its structural, electronic band structure, elastic, thermal, and optical characteristics, have been examined in this work utilizing density functional theory (DFT). The elastic constants indicate that {\rm LaMg}_2H_7 is mechanically stable, brittle in nature, and anisotropic. This studied compound possesses a moderate level of hardness. The band structure and density of states have been examined to have a better understanding of its electronic behavior. The intrinsic carrier concentrations and effective masses have been determined using the band structure. The gravimetric hydrogen storage capacity (Cwt%) has been calculated, indicating that this compound is suitable for hydrogen storage applications. This compound is dynamically stable, as confirmed by its phonon dispersion. Here, the details of this wide-band-gap semiconductor's reflectivity, absorption coefficient, refractive index, dielectric function, optical conductivity, and loss function are investigated. The substance is a moderate reflector of ultraviolet (UV) light. The absorption and conductivity support the gap in the band structure. The thermodynamic properties, such as bulk modulus, internal energy, specific heat capacity, entropy, thermal expansion coefficient, and Debye temperature, have been explored at varying temperatures and pressures. {\rm LaMg}_2H_7 has a moderate level of melting temperature with higher lattice thermal conductivity. The value of the thermal expansion coefficient and minimum thermal conductivity is highly recommended for use as a thermal barrier coating (TBC).