Magnetic exchange interactions in Mn doped ZnSnAs₂ chalcopyrite

Bouhani-Benziane, H.; Sahnoun, Omar; Sahnoun, Mohammed; Driz, Mohamed; Daul, Claude

doi:10.1016/j.jmmm.2015.08.025

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Journal article

Magnetic exchange interactions in Mn doped ZnSnAs₂ chalcopyrite

Bouhani-Benziane, H. Laboratoire de Physique Quantique de la Matière et Modélisation Mathématique (LPQ3M), University of Mascara, Algeria
Sahnoun, Omar Laboratoire de Physique Quantique de la Matière et Modélisation Mathématique (LPQ3M), University of Mascara, Algeria
Sahnoun, Mohammed Laboratoire de Physique Quantique de la Matière et Modélisation Mathématique (LPQ3M), University of Mascara, Algeria - Department of Chemistry, University of Fribourg, Switzerland
Driz, Mohamed Laboratoire de Sciences des Matériaux (LSM), University of Sidi Bel Abbes, Algeria
Daul, Claude Department of Chemistry, University of Fribourg, Switzerland

15.12.2015

Published in:

Journal of Magnetism and Magnetic Materials. - 2015, vol. 396, p. 345–349

English Accurate ab initio full-potential augmented plane wave (FP-LAPW) electronic calculations within generalized gradient approximation have been performed for Mn doped ZnSnAs₂ chalcopyrites, focusing on their electronic and magnetic properties as a function of the geometry related to low Mn-impurity concentration and the spin magnetic alignment (i.e., ferromagnetic vs antiferromagnetic). As expected, Mn is found to be a source of holes and localized magnetic moments of about 4 µ_B per Mn atom are calculated which are sufficiently large. The defect calculations are firstly performed by replacing a single cation (namely Zn and Sn) with a single Mn atom in the pure chalcopyrite ZnSnAs₂ supercell, and their corresponding formation energies show that the substitution of a Sn atom (rather than Zn) by Mn is strongly favored. Thereafter, a comparison of total energy differences between ferromagnetic (FM) and antiferromagnetic (AFM) are given. Surprisingly, the exchange interaction between a Mn pairs is found to oscillate with the distance between them. Consequently, the AFM alignment is energetically favored in Mn-doped ZnSnAs₂ compounds, except for low impurity concentration associated with lower distances between neighboring Mn impurities, in this case the stabilization of FM increases. Moreover, the ferromagnetic alignment in the Mn-doped ZnSnAs₂ systems behaves half-metallic; the valence band for majority spin orientation is partially filled while there is a gap in the density of states for the minority spin orientation. This semiconducting gap of ~1 eV opened up in the minority channel and is due to the large bonding–antibonding splitting from the p–d hybridization. Our findings suggest that the Mn-doped ZnSnAs₂ chalcopyrites could be a different class of ferromagnetic semiconductors.

Faculty

Faculté des sciences et de médecine

Department

Département de Chimie

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