Structural, magnetic, electronic, optical and mechanical properties of actinide perovskite oxides XAnO3 [X = Cs+, Ba2+; An = Np5+, Np4+]: GGA, GGA+U and GGA+U+mBJ investigations

Abstract

First-principles density functional theory (DFT)-based calculations were performed to investigate the structural, magnetic, electronic, optical and mechanical properties of two actinide perovskite oxides XAnO3, where [X = Cs+, Ba2+; An = Np5+, Np4+]. Wien2k software is utilized with GGA, GGA+U and GGA+U+mBJ potentials. The unit cell volumes for cubic (Pm-3m) structure of XAnO3 are optimized to achieve the ground state energy and equilibrium parameters. Substitution of X- and An-sites increases the lattice constant, = 4.3998 Å (X = Cs+) and = 4.4378 Å (X = Ba2+). The calculated band structure plus total and partial density of states using these methods confirm the 100% spin-polarization and half-metallic (HM) nature of XAnO3 with = 2.731, 3.896 and 3.787 eV (X = Cs+); 3.891, 3.929 and 4.329 eV (X = Cs+). Total magnetic moment per unit cell of XAnO3 is respectively = 2.0 and 3.0 μB revealing their ferromagnetic (FM) behavior with high Curie temperature () within GGA, GGA+U and GGA+U+mBJ. Mechanical and thermodynamic stability of XAnO3 have been proved via the elastic parameters, sound velocity, Debye and melting temperatures, and enthalpy of formation. In addition, XAnO3 show amazing optical responses include high absorption, conductivity, refractivity, and reflectivity. These investigated properties confirm that XAnO3 materials have FM-HM and high optical characteristics and they perfectly suitable for many spintronics and optoelectronics applications such as sensors, storage devices and photodiodes.