Chemical trend of exchange couplings in diluted magnetic II-VI semiconductors

Abstract

We have calculated the chemical trend of magnetic exchange parameters ($J_{dd}$, $N\alpha$, and $N\beta$) of Zn-based II-VI semiconductors ZnA (A=O, S, Se, and Te) doped with Co or Mn. We show that a proper treatment of electron correlations by the LSDA+$U$ method leads to good agreement between experimental and theoretical values of the nearest-neighbor exchange coupling $J_{dd}$ between localized 3$d$ spins in contrast to the LSDA method. The exchange couplings between localized spins and doped electrons in the conduction band $N\alpha$ are in good agreement with experiment as well. But the values for $N\beta$ (coupling to doped holes in the valence band) indicate a cross-over from weak coupling (for A=Te and Se) to strong coupling (for A=O) and a localized hole state in ZnO:Mn. That hole localization explains the apparent discrepancy between photoemission and magneto-optical data for ZnO:Mn.

arXiv comment19 pages, 4 figures

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Cited by in corpus (10)

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• Effects related to deposition temperature of ZnCoO films grown by Atomic Layer Deposition - uniformity of Co distribution, structural, optical, electrical and magnetic properties
• Metastability of Mn${}^{3+}$ in ZnO driven by strong $d$(Mn) intrashell Coulomb repulsion: experiment and theory
• Puzzling magneto-optical properties of ZnMnO films
• Chemical trends of substitutional transition metal dopants in diamond: an ab initio study
• Upper bound for the s-d exchange integral in n-(Ga,Mn)N:Si from magnetotransport studies
• Exchange couplings for Mn ions in CdTe: validity of spin models for dilute magnetic II-VI semiconductors
• Substitutional nickel impurities in diamond: decoherence-free subspaces for quantum information processing
• Calculated optical properties of Co in ZnO: internal and ionization transitions