The first-principle study on structural, mechanical, electronic and optical properties of half-metallic CaMSi2O6 (M= Co, Fe, Mn) clinopyroxenes

Abstract

Ca-based pyroxene structures have gained significant attention due to the higher abundances of calcium in the earth's crust and relatively easy synthesis process. Here, we have analyzed the structural, mechanical, elastic, thermal, and optoelectronic properties of CaMSi2O6 (M = Co, Fe, Mn) pyroxene structures in the monoclinic phase using the first-principles density functional theory (DFT) approach using CASTEP code. The lattice constants of the simulated structures in ferromagnetic (FM) orientations using GGA-WC and GGA-PBSOL were consistent with the available experimental data. Using the Born stability criteria, these structures are considered mechanically stable. These are elastically anisotropic and brittle compounds. The melting temperatures are in the order of 103 K which symbolizes these as potential candidates for high-temperature applications. The band structure alongside the electronic density of states at the Fermi level reveals half metallicity of these structures. CaMnSi2O6 structure has a maximum half-metallic gap of around 4.60 eV. The remaining two structures have an indirect band gap in the visible photon range given as 3.14 eV, and 2.65 eV for CaCoSi2O6, and CaMnSi2O6, respectively. Observing optical and electronic properties shows that the compound holds a promising future to be utilized in the optoelectronic and plasmonic fields.