title: Interfacial Symmetry Control of Emergent Ferromagnetism at the Nanoscale.
abstract: The emergence of complex new ground states at interfaces has been identified as one of the most promising routes to highly tunable nanoscale materials. Despite recent progress, isolating and controlling the underlying mechanisms behind these emergent properties remains among the most challenging materials physics problems to date. In particular, generating ferromagnetism localized at the interface of two nonferromagnetic materials is of fundamental and technological interest. Moreover, the ability to turn the ferromagnetism on and off would shed light on the origin of such emergent phenomena and is promising for spintronic applications. We demonstrate that ferromagnetism confined within one unit cell at the interface of CaRuO3 and CaMnO3 can be switched on and off by changing the symmetry of the oxygen octahedra connectivity at the boundary. Interfaces that are symmetry-matched across the boundary exhibit interfacial CaMnO3 ferromagnetism while the ferromagnetism at symmetry-mismatched interfaces is suppressed. We attribute the suppression of ferromagnetic order to a reduction in charge transfer at symmetry-mismatched interfaces, where frustrated bonding weakens the orbital overlap. Thus, interfacial symmetry is a new route to control emergent ferromagnetism in materials such as CaMnO3 that exhibit antiferromagnetism in bulk form.
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.|NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.|Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States.
authors.forename: A J
authors.initials: AJ
authors.lastname: Grutter
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.
authors.forename: A
authors.initials: A
authors.lastname: Vailionis
authors.affiliation: NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: J A
authors.initials: JA
authors.lastname: Borchers
authors.affiliation: NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: B J
authors.initials: BJ
authors.lastname: Kirby
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.|Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: C L
authors.initials: CL
authors.lastname: Flint
authors.affiliation: Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States.
authors.forename: C
authors.initials: C
authors.lastname: He
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: E
authors.initials: E
authors.lastname: Arenholz
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.|Department of Applied Physics, Stanford University , Stanford, California 94305, United States.
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
keywords: Magnetism; charge transfer; interfacial properties; interfacial symmetry; perovskite; superlattice