Electronic structure alteration in MgO monolayer through alkali metal doping

Abstract

We have studied the structural and electronic properties of MgO monolayer (ML) by substituting one of its Mg sites with alkali metal atoms (Li, Na, K) using DFT calculations in Quantum ESPRESSO. All the planar-doped monolayers are structurally stable shown by the computed binding energy per atom values. Formation energies suggest that Li exhibits the strongest binding with MgO ML. Doping turns the non-magnetic semiconducting MgO MLs into half-metallic magnets with magnetic moment of ∼ 1μB. The corresponding magnetic states are contributed by the valence orbitals of O atoms near the doping sites. Thus, Li, Na, K substitution introduces huge changes in electronic structure and properties of MgO ML.