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

Abstract

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.