Structural, electronic and magnetic properties of the (Co, Ni) codoped ZnS: A first-principles study

• Zn31Co1S32Zn31Co1S32 is magnetic semiconductor, while Zn31Ni1S32Zn31Ni1S32 is magnetic half-metal.
• Zn30Co1Ni1S32Zn30Co1Ni1S32 exhibits a half-metallic ferrimagnetic character.
• Total magnetic moments are mainly contributed by 3d orbital of Co and Ni dopants.
• Co and Ni dopants favorably occupy the nearest positions with antiparallel moments.
• Hybridization between Co or Ni dopant and its nearest S atoms reduces its moment.

Using spin-polarized first-principles calculation, we investigate the structural, electronic and magnetic properties of the Zn31Co1S32Zn31Co1S32, Zn31Ni1S32Zn31Ni1S32 and Zn30Co1Ni1S32Zn30Co1Ni1S32 systems. The results show that the Zn31Co1S32Zn31Co1S32 system is a magnetic semiconductor, while the Zn31Ni1S32Zn31Ni1S32 system exhibits a magnetic half-metallic (HM) character. The Zn30Co1Ni1S32Zn30Co1Ni1S32 system exhibits a HM ferrimagnetic character explained by the superexchange mechanism. The Co and Ni atoms favorably occupy nearest neighbor positions of the metal sublattice with antiparallel arrangement of their magnetic moments. Furthermore, it is observed that the magnetic moment of Co/Ni atom reduces from an isolated atom magnetic moment due to p–d hybridization which yields small parallel magnetic moments on the nearest S atoms.