Probing the Origin of Interfacial Carriers in SrTiO 3 –LaCrO 3 Superlattices

Comes, Ryan B.; Spurgeon, Steven R.; Kepaptsoglou, Despoina M.; Engelhard, Mark H.; Perea, Daniel E.; Kaspar, Tiffany C.; Ramasse, Quentin M.; Sushko, Peter V.; Chambers, Scott A.

doi:10.1021/acs.chemmater.6b04329

Probing the Origin of Interfacial Carriers in SrTiO ₃ –LaCrO ₃ Superlattices

Journal Article · Thu Jan 26 04:00:00 EST 2017 · Chemistry of Materials

DOI:https://doi.org/10.1021/acs.chemmater.6b04329· OSTI ID:1344625

; ; Kepaptsoglou, Despoina M.; Engelhard, Mark H.; ; Kaspar, Tiffany C.; Ramasse, Quentin M.; Sushko, Peter V.; Chambers, Scott A.

Emergent phenomena at complex oxide interfaces could provide the basis for a wide variety of next-generation devices, including photovoltaics and spintronics. To date, detailed characterization and computational modeling of interfacial defects, cation intermixing, and film stoichiometry have helped to explain many of the novel behaviors observed at a single heterojunction. Unfortunately, many of the techniques employed to characterize a single heterojunction are less effective for a superlattice made up of a repeating series of interfaces that induce collective interfacial phenomena throughout a film. However, these repeating interfaces present an untapped opportunity to introduce an additional degree of complexity, such as confined electric fields, that cannot be studied in a single heterojunction. In this work, we explore the properties of SrTiO3-LaCrO3 superlattices to understand the role of defects, including variations in cation stoichiometry of individual layers of the superlattice, intermixing across interfaces, and interfacial oxygen vacancies. Using x-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy electron energy-loss spectroscopy (STEM-EELS), we quantify the stoichiometry of individual layers of the superlattice and determine the degree of intermixing in these materials. By comparing these results to both density functional theory (DFT) models and STEM-EELS measurements of the Ti and Cr valence in each layer of the superlattice, we correlate different types of defects with the associated materials properties of the superlattice. We show that a combination of ab initio modeling and complementary structural characterization methods can offer unique insight into structure-property relationships in many oxide superlattice systems.

Research Organization:: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)

Sponsoring Organization:: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)

DOE Contract Number:: AC05-76RL01830

OSTI ID:: 1344625

Report Number(s):: PNNL-SA-119292; 49306

Journal Information:: Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 3 Vol. 29; ISSN 0897-4756

Publisher:: American Chemical Society (ACS)

Country of Publication:: United States

Language:: English

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Cited By (2)

Strain-induced indirect-to-direct bandgap transition in an np-type LaAlO ₃ /SrTiO ₃ (110) superlattice Wang, L.; Pan, W.; Hu, W. X. Physical Chemistry Chemical Physics, Vol. 21, Issue 13 https://doi.org/10.1039/c8cp07761d	journal	January 2019
Interface properties and built-in potential profile of a LaCr O 3 / SrTi O 3 superlattice determined by standing-wave excited photoemission spectroscopy Lin, S. -C.; Kuo, C. -T.; Comes, R. B. Physical Review B, Vol. 98, Issue 16 https://doi.org/10.1103/physrevb.98.165124	journal	October 2018

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