Persistent half-metallic ferromagnetism in a (111)-oriented manganite superlattice

We employ electronic structure calculations to show that a (111)-oriented (LaMnO3)(12) divide (SrMnO3)(6) superlattice retains a half-metallic ferromagnetic character despite its large thickness. We link this behaviour to the strain and the octahedral connectivity between the layers. This also gives rise to breathing modes, which are coupled to charge and spin oscillations, whose components have a pure e(g) character. Most interestingly, the magnetisation reaches its maximum value inside the LaMnO3 region and not at the interface, which is fundamentally different from what observed for the (001) orientation. The inter-atomic exchange coupling shows that the magnetic order arises from the double-exchange mechanism, despite competing interactions inside the SrMnO3 region. Finally, the van Vleck distortions and the spin oscillations are crucially affected by the variation of Hund's exchange and charge doping, which allows us to speculate that our system behaves as a Hund's metal, creating an interesting connection between manganites and nickelates.

Automated summary

Using electronic structure calculations, we demonstrate that a (111)-oriented (LaMnO3)(12)/(SrMnO3)(6) superlattice maintains a half-metallic ferromagnetic character despite its large thickness, which is attributed to strain and octahedral connectivity between the layers. Interestingly, the maximum magnetization is observed inside the LaMnO3 region rather than at the interface, in contrast to the behavior observed for the (001) orientation. The inter-atomic exchange coupling suggests that the magnetic order arises from the double-exchange mechanism, despite competing interactions inside the SrMnO3 region.