Interface-induced Polarization in SrTiO${}_3$-LaCrO${}_3$ Superlattices

Abstract

Epitaxial interfaces and superlattices comprised of polar and non-polar perovskite oxides have generated considerable interest because they possess a range of desirable properties for functional devices. In this work, emergent polarization in superlattices of SrTiO${}_3$ (STO) and LaCrO${}_3$ (LCO) is demonstrated. By controlling the interfaces between polar LCO and non-polar STO, polarization is induced throughout the STO layers of the superlattice. Using x-ray absorption near-edge spectroscopy and aberration-corrected scanning transmission electron microscopy displacements of the Ti cations off-center within TiO6 octahedra along the superlattice growth direction are measured. This distortion gives rise to built-in potential gradients within the STO and LCO layers, as measured by in situ x-ray photoelectron spectroscopy. Density functional theory models explain the mechanisms underlying this behavior, revealing the existence of both an intrinsic polar distortion and a built-in electric field, which are due to alternately positively and negatively charged interfaces in the superlattice. This study paves the way for controllable polarization for carrier separation in multilayer materials and highlights the crucial role that interface structure plays in governing such behavior.

arXiv comment19 pages, 3 figures, supplement: 13 pages, 7 figures, Advanced Materials Interfaces, Early View, 2016

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Cited by in corpus (8)

• Photoferroelectric oxides
• The effect of intrinsic point defects on ferroelectric polarization behavior of SrTiO${}_3$
• Interface structure, band alignment and built-in potentials at LaFeO${}_3$/$\text{n}$-SrTiO${}_3$ heterojunctions
• Probing Emergent Surface and Interfacial Properties in Complex Oxides via in situ X-ray Photoelectron Spectroscopy
• Dynamic Interface Rearrangement in LaFeO${}_3$ / $n$-SrTiO${}_3$ Heterojunctions
• Interface properties and built-in potential profile of a LaCrO${}_3$/SrTiO${}_3$ superlattice determined by standing-wave excited photoemission spectroscopy
• Emergent phenomena at oxide interfaces studied with standing-wave photoelectron spectroscopy
• Probing the polar-nonpolar oxide interfaces using resonant x-ray standing wave techniques