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March 5, 2026International Journal of Modern Physics B0 citations

DFT investigation of mechanical stability, optical response and high-temperature thermoelectric efficiency in cubic Cu 2 Se

MUMuhammad UzairUniversity of Peshawar NSNourreddine SfinaKing Khalid University MAM. D. AlshahraniUniversity of Bisha

Key Points

The aim is to investigate the structural, electronic, optical, elastic, and thermoelectric properties of cubic Cu2Se.
Structural optimization using LDA, PBE-GGA, and PBEsol-GGA
Elastic constant calculations to assess mechanical stability
Electronic structure analysis to determine conductivity
Optical response evaluation for dielectric properties
Thermoelectric transport calculations to predict efficiency
Lattice constants found to be 5.663, 5.847, and 5.730 Å based on different GGA methods
Elastic constants indicate mechanical stability with a high Pugh's ratio
Semi-metallic behavior was noted; density of states at the Fermi level reduced by mBJ-GGA
Static dielectric constant reached 48 in GGA; significant ultraviolet absorption observed
Maximum thermoelectric figure of merit ZT of 0.28 predicted at 1000K

Abstract

This study presents a comprehensive first-principles investigation of cubic Cu 2 Se, focusing on its structural, electronic, optical, elastic and thermoelectric properties using density functional theory (DFT). Structural optimization using LDA, PBE-GGA and PBEsol-GGA yields lattice constants of 5.663, 5.847 and 5.730 Å, respectively, with PBE-GGA providing the lowest ground-state energy and an equilibrium volume of 337.22 a.u. 3 . The calculated elastic constants (Formula: see text Formula: see text 97.23Formula: see textGPa, Formula: see text Formula: see textGPa and Formula: see text Formula: see text 58.03Formula: see textGPa) confirm mechanical stability and ductile behavior with a high Pugh’s ratio (B/Formula: see text) and strong elastic anisotropy (Formula: see text). Electronic structure analysis reveals semi-metallic behavior, with mBJ-GGA reducing the density of states at the Fermi level. Optical calculations show a high static dielectric constant (Formula: see text48 in GGA and Formula: see text17 in mBJ-GGA), strong ultraviolet absorption exceeding Formula: see text Formula: see textcmFormula: see text, and a pronounced plasmon peak near 22 eV in the energy loss spectrum. Thermoelectric transport calculations predict a maximum figure of merit of ZT Formula: see text 0.28 at 1000Formula: see textK within the GGA framework, indicating the suitability of Cu 2 Se for mid-temperature thermoelectric applications.

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