Interface-Induced Polarization in SrTiO ₃ -LaCrO ₃ Superlattices

Journal Article · Mon Feb 29 04:00:00 EST 2016 · Advanced Materials Interfaces

DOI:https://doi.org/10.1002/admi.201500779· OSTI ID:1245896

Comes, Ryan B. ^[1]; Spurgeon, Steven R. ^[1]; Heald, Steve M. ^[2]; Kepaptsoglou, Despoina M. ^[3]; Jones, Lewys ^[4]; Ong, Phuong Vu ^[1]; Bowden, Mark E. ^[5]; Ramasse, Quentin M. ^[3]; Sushko, Peter V. ^[1]; Chambers, Scott A. ^[1]

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1. Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA
2. Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA
3. SuperSTEM, SciTech Daresbury Campus, Daresbury WA44AD UK
4. Department of Materials, University of Oxford, Oxford OX13PH UK
5. Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA

Epitaxial interfaces and superlattices comprised of polar and non-polar perovskite oxides have generated a good deal of interest because of the variety of novel properties they possess. In this work, we examine superlattices comprised of SrTiO3 (STO) and LaCrO3 (LCO) layers; we demonstrate that the differing band alignment of the polar LCO layer and the non-polar STO layer produces a ferroelectric phase transition throughout the STO layers of the superlattice. Through x-ray absorption near edge spectroscopy and aberration-corrected scanning transmission electron microscopy we show that the Ti cations are displaced off-center in the TiO6 octahedra along the superlattice growth direction. We also demonstrate that a built-in potential gradient exists within the STO and LCO layers via in situ x-ray photoelectron spectroscopy measurements. Density functional theory models of the system are in excellent agreement with these results, predicting both the ferroelectric octahedral distortion and the built-in electric field. These results represent a new avenue for research in perovskite superlattices, as two non-ferroelectric phases are shown to induce a bulk ferroelectric response due to interfacial phenomena.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1245896
• Report Number(s): PNNL-SA-111839; 48341
• Journal Information: Advanced Materials Interfaces, Journal Name: Advanced Materials Interfaces Journal Issue: 10 Vol. 3; ISSN 2196-7350
• Publisher: Wiley-VCH
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory
complex oxides
ferroelectrics
superlattices
x-ray absorption spectroscopy
x-ray photoelectron spectroscopy