Evaluation of thermodynamics and p-type ferromagnetism of C, Si and Ge doped ZnX (X = S, Se and Te) semiconductors

Abstract

Abstract The defect formation energetics, electronic structure and ferromagnetic properties of carbon group IVA atoms (C, Si and Ge) doped zinc-blende ZnX (X = S, Se and Te) semiconductors are studied using first-principles density functional theory calculations by employing the full-potential linear augmented plane wave (FP-LAPW) method. The thermodynamics of doping carbon, silicon and germanium in the zinc chalcogenide semiconductors are examined for valid limits of the atomic chemical potentials of the atomic species. Our results reveal that some of the non-magnetic carbon group dopants are able to induce long range stable ferromagnetism in ZnX semiconductors. The calculated magnetic moment in the supercell structures are found to be dependent on the electronegativity difference and the bond length between the host and the dopant species. Spontaneous spin-polarization of the electronic structure of doped systems has been found to decrease with increasing hybridization of dopant’s 2p/3p/4p states with the Zn-3d states. We show that the magnetic moments in the doped systems originate from the atomic like character of the localized p orbitals of the dopant atom which only loses its atomic character with increase in the charge transfer from Zn and chalcogen atoms to the carbon group dopant atoms.