Ab initio study on the role of the crystalline symmetry in the stabilization of the magnetic order in Al-doped SnS

E. A. ALBANESI; C.I. ZANDALAZINI

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2019 vol. 487 p. 146 - 153

0304-8853

We use first principles calculations to study the electronic and magnetic properties of undoped and Al-doped SnSand their dependence with space-group symmetry. The formation of a magnetic moment due to an impurityelement was analyzed by substitutional doping in Pnma(62)-SnS and C2mb(39)-SnS symmetries. The holes introducedby cation Al-doping leads to the formation of a magnetic moment of 1.0 μB/impurity, and a halfmetallicbehavior. Orbital configurations with local magnetic moments are established due to strong hybridizationbetween {s;p}-Al orbitals and {s;p}-S orbitals. The collective magnetic order was analyzed by theeffective exchange-coupling parameters between Al atoms at different atomic cationic sites, and different holeconcentrations. These results indicate that the stabilization of the magnetic order presents a strong dependencewith the spatial arrangement and the exchange pathways. For nearby dopants, and at the same holes concentration,both the Pnma and the C2mb symmetries present an AFM behavior. This collective magnetic orderchanges to a ferromagnetic coupling for the case in which the dopants are further away or when there is a higherholes concentration. The origin of such magnetic ordering can be understood based on the competition betweenhole-mediated superexchange and double exchange mechanisms. Our predictive results offer the possibility todistinguish between holes doping effect and the role of symmetry in the coordination of the dopant, of greatimportance to the understanding of the origin of defect-induced magnetism.