  The mechanical, structural, electronic and magnetic properties of s-triazine
sheet (C6N6) with embedded Mn atom (Mn-C6N6) is investigated under the
influence of external environment using density functional theory. Our results
show that Mn-C6N6 system is structurally and mechanically stable. The binding
energy of Mn embedded in C6N6 sheet can be modulated under the influence of
symmetric deformation and perpendicular electric field respectively. The
semiconducting property of pure C6N6 sheet is maintained upon embedment of Mn
atom in the porous site. It is also found that small increment in bi-axial
tensile strain enhances the band gap (from 0.630 eV at zero strain to 0.802 eV
at 5% strain) while the magnetic moment of the embedded Mn atom is preserved.
The electronic and magnetic properties of the Mn-C6N6 systems are maintained up
to 10 V/nm in electric field strength. We also explore the geometries,
electronic and magnetic properties of Mn-C6N6 with adsorbed atoms and
molecules. The Mn-C6N6 with adsorbed O atom and O2 molecule systems shows
half-metallic character whereas the remaining systems preserve their
semiconducting property. The total magnetic moment per unit cell in most of the
systems is found to reduce as compared to that of the Mn-C6N6 sheet. The
reduction in magnetic moment can be related to the strong interactions among
the Mn atom and the surrounding atoms which lead to the formation of low-spin
configurations. Overall, our results indicate that the Mn-C6N6 systems with and
without adsorbed atoms and molecules can serve as potential candidates for
future spintronics and catalysis applications.
