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<p>Using density functional theory, we present a first-principles study of quaternary chalcogenides ACdCu<sub>2</sub>Se<sub>4</sub> (A = Sc, Y). Negative formation energies (− 1.231&#xa0;eV/atom for Sc and − 1.365&#xa0;eV/atom for Y) confirms thermodynamic stability. Structural optimization within GGA-PBE and a parabolic equation of state indicate structural stability. Elastic constants satisfy the Born criteria, with Pugh’s ratios (0.61 for Sc and 0.65 for Y) and negative Cauchy pressures indicating brittle, covalent behavior. While PBE predicts metallicity, the mBJ approach reveals both compounds as indirect semiconductors, with Cu-3<i>d</i>/Se-4<i>p</i> states dominating the valence band and Cd-s and Sc(Y)-d states contributing to the conduction band. Strong optical absorption (~ 9 × 10<sup>5</sup>&#xa0;cm<sup>−1</sup>) in the UV range is observed near 2.5–3.0&#xa0;eV. Phonon dispersion shows no imaginary modes, confirming dynamical stability. Debye temperatures of 318.96&#xa0;K (Sc) and 308.15&#xa0;K (Y), sound velocities around 4600–4730&#xa0;m/s, and melting temperatures near 1040&#xa0;K indicate stable thermal behavior. Overall, the mechanical, electronic, optical, and thermal properties confirm phase stability, highlighting ACdCu<sub>2</sub>Se<sub>4</sub> (A = Sc, Y) as promising materials for optoelectronic, thermoelectric, and photovoltaic applications.</p>

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Thermo-mechanical stability and strong optical absorption in quaternary chalcogenides ACdCu3Se4 (A = Sc, Y): a first-principles study

  • 期刊论文

  • 发表日期：

    2026年6月24日

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  • Ahmed Azzouz-Rached,
  • Amir Ullah,
  • Mubashir Hussain,
  • Eman M. Alshehri,
  • Vineet Tirth,
  • Ali Algahtani,
  • Saleha Qissi,
  • Wafa S. Aljuaid,
  • Essam A. Al-Ammar,
  • Nasir Rahman,
  • Mudasser Husain

摘要

Using density functional theory, we present a first-principles study of quaternary chalcogenides ACdCu2Se4 (A = Sc, Y). Negative formation energies (− 1.231 eV/atom for Sc and − 1.365 eV/atom for Y) confirms thermodynamic stability. Structural optimization within GGA-PBE and a parabolic equation of state indicate structural stability. Elastic constants satisfy the Born criteria, with Pugh’s ratios (0.61 for Sc and 0.65 for Y) and negative Cauchy pressures indicating brittle, covalent behavior. While PBE predicts metallicity, the mBJ approach reveals both compounds as indirect semiconductors, with Cu-3d/Se-4p states dominating the valence band and Cd-s and Sc(Y)-d states contributing to the conduction band. Strong optical absorption (~ 9 × 105 cm−1) in the UV range is observed near 2.5–3.0 eV. Phonon dispersion shows no imaginary modes, confirming dynamical stability. Debye temperatures of 318.96 K (Sc) and 308.15 K (Y), sound velocities around 4600–4730 m/s, and melting temperatures near 1040 K indicate stable thermal behavior. Overall, the mechanical, electronic, optical, and thermal properties confirm phase stability, highlighting ACdCu2Se4 (A = Sc, Y) as promising materials for optoelectronic, thermoelectric, and photovoltaic applications.