Structural, electronic, mechanical, optical, and thermodynamic properties of novel quaternary oxychalcogenide LaCuTeO for optoelectronic applications

We present a comprehensive first-principles study of the newly proposed quaternary oxychalcogenide LaCuTeO with tetragonal P4/nmm symmetry, combining ab initio DFT calculations to explore its potential for optoelectronic applications. Using the full-potential linearized augmented plane wave (FP-LAPW) method within the WIEN2k code, we systematically investigated the structural, electronic, elastic, optical, and thermodynamic properties. The optimized lattice parameters are a = b = 4.101 Å and c = 9.062 Å with a bulk modulus of 108.33 GPa, confirming excellent structural stability. Phonon dispersion calculations reveal dynamic stability with no imaginary frequencies. Electronic band structure calculations using LDA and LDA + U (U = 6 eV) predict a direct bandgap of 0.999 eV and 1.324 eV, respectively, suitable for visible-to-near-infrared optoelectronic and photovoltaic applications. The elastic constants satisfy all mechanical stability criteria with a universal anisotropy index of 4.58 and Vickers hardness of 24.70 GPa (Chen model), indicating significant mechanical resilience. Optical properties demonstrate strong absorption in the visible-UV range with refractive indices of 3.253 (nxx) and 3.061 (nzz) at zero frequency, suggesting promising applications in photovoltaic and photocatalytic devices. Thermodynamic analysis shows heat capacity approaching the Dulong–Petit limit (99.45 J/mol·K) at high temperatures. Furthermore, the calculated electronic and optical characteristics reveal favorable carrier transport properties and strong light–matter interaction, highlighting the suitability of LaCuTeO for efficient solar energy harvesting and optoelectronic device performance. Our comprehensive computational study establishes LaCuTeO as a promising multifunctional material for next-generation optoelectronic technologies.