Polar catastrophe, electron leakage, and magnetic ordering at the LaMnO${}_3$/SrMnO${}_3$ interface

Abstract

Electronic reconstruction at the polar interface LaMnO${}_3$/SrMnO${}_3$ (LMO/SMO) (100) resulting from the polar catastrophe is studied from a model Hamiltonian that includes the double and super exchange interactions, the Madelung potential, and the Jahn-Teller coupling terms relevant for the manganites. We show that the polar catastrophe, originating from the alternately charged LMO layers and neutral SMO layers, is quenched by the accumulation of an extra half electron per cell in the interface region as in the case of the LaAlO${}_3$/SrTiO${}_3$ interface. In addition, the Mn e${}_g$ electrons leak out from the LMO side to the SMO side, the extent of the leakage being controlled by the interfacial potential barrier and the substrate induced epitaxial strain. The leaked electrons mediate a Zener double exchange, making the layers adjacent to the interface ferromagnetic, while the two bulk materials away from the interface retain their original type A or G antiferromagnetic structures. A half-metallic conduction band results at the interface, sandwiched by the two insulating bulks. We have also studied how the electron leakage and consequently the magnetic ordering are affected by the substrate induced epitaxial strain. Comparisons are made with the results of the density-functional calculations for the (LMO)${}_6$/(SMO)${}_4$ superlattice.

8 pages, 13 figures

References in corpus (6)

• Magnetic effects at the interface between nonmagnetic oxides
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• Towards two-dimensional metallic behavior at LaAlO3/SrTiO3 interfaces
• Metal-insulator transition in $(LaMn{O}_3{)}_{2n}/(SrMn{O}_3{)}_n$ superlattices
• Magnetically asymmetric interfaces in a (LaMnO${}_3$)/(SrMnO${}_3$) superlattice due to structural asymmetries
• Evolution of magnetic phases and orbital occupation in (SrMnO3)n/(LaMnO3)2n superlattices

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• Magnetic and Orbital Order in ($R$MnO${}_3$)${}_n$/($A$MnO${}_3$)${}_{2n}$ Superlattices Studied via a Double-Exchange Model with Strain
• Persistent half-metallic ferromagnetism in a (111)-oriented manganite superlattice
• Structural and electronic phenomena at oxyfluoride KTaO${}_3$/K$M$F${}_3$ ($M$ = Zn and Ni) superlattices: Rashba splitting and 2DEG
• Electron-lattice and strain effects in manganite heterostructures: the case of a single interface
• Emergent half-metal with mixed structural order in (111)-oriented (LaMnO${}_3$)${}_{2n}$|(SrMnO${}_3$)${}_n$ superlattices
• Charge ordering at the interface in (LaMnO${}_3$)${}_{2n}$/(SrMnO${}_3$)${}_n$ superlattices as the origin of their insulating state