A DFT study of the halide inorganic LiBeI3 perovskite

Abstract

This work investigates the structural, elastic, mechanical, electronic, optical, and thermoelectric properties of the novel inorganic halide perovskite compound LiBeI₃ using density functional theory (DFT) within the Wien2k package. Our theoretical analysis provides fundamental insights into the nature of this compound, revealing that LiBeI₃ is a semiconductor with an indirect bandgap of 0.434 eV. The electronic and optical properties were analyzed in detail, including the electronic energy loss function, absorption coefficient, real and imaginary components of the dielectric function, and optical conductivity. Notably, LiBeI₃ exhibits strong absorption in the UV region, making it a promising candidate for photovoltaic applications. Its high absorption coefficient also suggests potential use in light-emitting diodes (LEDs) and laser technologies. Furthermore, we explored its thermoelectric behavior by calculating the electrical conductivity, Seebeck coefficient, and electronic thermal conductivity. The positive temperature coefficient (PTC) effect observed in the Seebeck coefficient indicates an increasing power factor with temperature, a characteristic feature of semiconductors and semimetals. This behavior is critical for understanding the thermoelectric efficiency of LiBeI₃, highlighting its potential for energy harvesting applications based on temperature gradients. Our findings contribute to the growing interest in halide perovskites and suggest that LiBeI₃ could serve as a multifunctional material for optoelectronic and thermoelectric technologies.