Ferroelectric PbTiO${}_3$/SrRuO${}_3$ superlattices with broken inversion symmetry

Abstract

We have fabricated PbTiO${}_3$/SrRuO${}_3$ superlattices with ultra-thin SrRuO${}_3$ layers. Due to the superlattice geometry, the samples show a large anisotropy in their electrical resistivity, which can be controlled by changing the thickness of the PbTiO${}_3$ layers. Therefore, along the ferroelectric direction, SrRuO${}_3$ layers can act as dielectric, rather than metallic, elements. We show that, by reducing the concentration of PbTiO${}_3$, an increasingly important effect of polarization asymmetry due to compositional inversion symmetry breaking occurs. The results are significant as they represent a new class of ferroelectric superlattices, with a rich and complex phase diagram. By expanding our set of materials we are able to introduce new behaviors that can only occur when one of the materials is not a perovskite titanate. Here, compositional inversion symmetry breaking in bi-color superlattices, due to the combined variation of A and B site ions within the superlattice, is demonstrated using a combination of experimental measurements and first principles density functional theory.

To be published in Physical Review Letters

References in corpus (3)

• Structural, electronic and magnetic properties of SrRuO${}_3$ under epitaxial strain
• Electronic properties of bulk and thin film SrRuO${}_3$: a search for the metal-insulator transition
• Highly-confined spin-polarized two-dimensional electron gas in SrTiO${}_3$/SrRuO${}_3$ superlattices

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• Interface-induced Polarization in SrTiO${}_3$-LaCrO${}_3$ Superlattices
• Correlated Quantum Phenomena of Spin-Orbit Coupled Perovskite Oxide Heterostructures: Cases of SrRuO3 and SrIrO3-Based Artificial Superlattices
• Interplay of Coulomb Blockade and Ferroelectricity in Nano-Granular Materials
• Theory of polarization textures in crystal supercells
• Atomistic Engineering of Phonons in Functional Oxide Heterostructures
• Origin of the kink in the band dispersion of the ferromagnetic perovskite SrRuO3: Electron-phonon coupling
• Electrostatics and domains in ferroelectric superlattices
• Interplay of ferroelectricity and single electron tunneling
• Memory effect in ferroelectric single electron transistor: violation of conductance periodicity in the gate voltage
• Giant electroresistance and tunable magnetoelectricity in a multiferroic junction