THEORETICAL PREDICTION OF INSTABILITY AND HALF-METALLICITY IN THE NaCaO3 PEROVSKITE: A DFT APPROACH

The structural, mechanical, electronic, and vibrational properties of the NaCaO₃ perovskite compound were examined using density functional theory (DFT) within the Quantum ESPRESSO software package. The calculations employed the plane-wave pseudopotential method. Mechanical analysis shows that the bulk-to-shear modulus ratio (B/G = 7.03) suggests ductile behavior, whereas the elastic stability criterion is not satisfied due to a negative value of C₄₄ (–4.42 GPa), indicating that the structure is mechanically unstable. The electronic band structure further reveals that NaCaO₃ exhibits half-metallicity: the spin-up channel displays semiconducting features with a direct bandgap of 4.69 eV, while the spin-down channel demonstrates metallic behavior. The density of states (DOS) analysis indicates that the conduction band is primarily derived from Ca-4d orbitals, while the valence band is dominated by O-2p orbitals. These results provide important insights into the intrinsic properties of NaCaO₃, emphasizing its potential for spintronic and electronic applications. Nevertheless, additional investigations using alternative computational approaches are recommended to validate and complement these findings.