Computational study of the lattice type, band structure, and thermoelectric properties of LiSbX2 (X = S, Se, Te)

Abstract

Chalcogenide materials have garnered significant attention for their excellent performance in optoelectronic and thermoelectric applications. This study explores the band structure and thermoelectric properties of ternary chalcogenides LiSbX₂ (X = S, Se. Te) using density functional theory (DFT). Our analysis reveals that these compounds exhibit negative formation energies and positive phonon frequencies, indicating their stability and a possible easy synthesis. The band structure calculations show that LiSbX₂ (X = S, Se, Te) are indirect bandgap semiconductors with a band gap of 0.96 (LiSbS₂), 0.52 (LiSbSe₂), and 0.13 eV (LiSbTe₂). Notably, these materials exhibit a high Seebeck coefficient, low electronic thermal conductivity, and high electronic conductivity. The maximum figure of merit is 0.61, 0.57, and 0.31 for LiSbS₂, LiSbSe₂, and LiSbTe₂, respectively, at 1000 K. These findings highlight the suitability of these compounds for future thermoelectric applications.