Pressure dependent characteristics of spinels AIn2S4 (A = Fe, Ni) for spintronic applications: mechanical stable, thermodynamic and spin-polarized electronic behavior

초록

Spintronics is an emerging route for next-generation electronics that exploits spin-polarized materials, typically realized in semiconductors and metal through intrinsic magnetic orderings. In current work, mechanical, structural, thermodynamic, and electronic properties for AIn2S4 (A = Fe, Ni) spinels are examined in detail utilizing density functional theory (DFT) calculations. Optimized lattice parameters are 10.53 & Aring; for FeIn2S4 and 10.43 & Aring; for NiIn2S4, in close agreement with reported experimental values. The formation enthalpies of -0.91 eV for FeIn2S4 and -0.80 eV for NiIn2S4 indicate that both compounds are thermodynamically stable, with the FeIn2S4 phase being comparatively more stable. The elasticity demonstrates mechanical stability and ductility, as shown by Poisson's ratios of 0.29 and 0.30 and B0/G values of 2.05 and 2.16 for FeIn2S4 and NiIn2S4, respectively. Spin-polarized band structures and density of states (DOS) represent half-metallic nature and the bandgap progressively increase as pressure increases from 0 to 4 GPa for spin up channel for both spinels. The computed total magnetic moment of 4 & micro;B f.u.-1 for FeIn2S4 and 2 & micro;B f.u.-1 for NiIn2S4 mainly stems from Fe/Ni ions, which is characteristic of ferromagnetic order. Thermodynamic parameters, including entropy and Debye temperature, obtained using the quasi-harmonic Debye model reveal signs of lattice stiffening, phonon softening, and anharmonicity. Overall, these findings confirm that AIn2S4 (A = Fe, Ni) spinels possess thermal stability and strong vibrational features, thereby making them suitable candidates for spintronics and magneto-electronic devices.

키워드