The role of Co atoms in spin dependent electronic properties of graphite-like ZnO structures

•Co dopants at distinct locations yield crucial changes in spin dependent behavior.•Spin dependent behavior is determined by atomic arrangement in Co doped ZnO systems.•Atomic configuration and Co concentration play a crucial role on minority band gap.•The magnetic moment is mostly contributed by Co-3d and O-2p orbitals.

A first principles study is employed to reveal the electronic properties of graphite-like Co doped ZnO structures composed of atomic layers when spin property of electrons is involved. The influence of Co atoms, which are substituting the Zn atoms, was addressed through distinct atomic arrangements formed by specific atomic configurations and various Co concentrations. We obtained that the spin dependent behavior is largely determined by the atomic arrangement which can crucially impact the electronic structure for a certain spin orientation. It was observed that atomic configuration is an essential factor which may reduce or enhance the minority-spin energy gap relative to majority one. It was shown that the emerging spin polarization can be manipulated by the atomic arrangement of the layered structures. Both the spin polarization and the magnetic moment were found to be contributed by both Co and O atoms. The stability of a system via formation energy, the role of Co dopants positioned at different Zn sites, the number of both Co atoms and layers in a supercell, and the mechanisms governing the spin dependent behavior of these structures are discussed.