Structural, electronic, magnetic, optical and thermoelectric response of half-metallic AMnTe2 (A = Li, Na, K): An ab-initio calculations

Highlights: • First principle calculations of structural, electronic, magnetic, optical and thermoelectric properties of manganese based half metallic compounds. • All the studied materials have an indirect band gap in spin-down (↓) channel, while metallic at spin up. • The opticl properties exhibit the materials are applicable on infrared region. -- Abstract: The structural, electronic, magnetic, optical and thermoelectric properties of manganese based half-metallic compounds AMnTe₂ (A = Li, Na, K) are carried out by employing Full Potential Linearized Augmented Plane Wave (FP-LAPW) method. Perdew-Burke-Ernzerhof-Generalized-Gradient-Approximations (PBE-GGA) are used for the exchange-correlation potential. Various properties of the compounds (LiMnTe₂, NaMnTe₂ and KMnTe₂) are investigated, such as the analysis of the density of states and spin-polarized band structures reveal that all the studied materials have an indirect bandgap in spin-down ($\downarrow$) channel, while spin-up $(\uparrow )$ channel exhibit metallic behavior. The stability of ferromagnetic nature is predicted by exchange energies, crystal field energies and John-Teller distortion. The absorption and extinction coefficient, dielectric constant, reflectivity, refractive index, energy loss function and optical conductivity are calculated through optical properties. The thermoelectric response of these materials is computed by employing BoltzTraP code. In addition, the phonon dispersion curves are calculated to examine the thermal stability of the materials.