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Title: Probing the Origin of Interfacial Carriers in SrTiO 3$-$LaCrO 3 Superlattices

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. These repeating interfaces present an untapped opportunity to introduce an additional degree of complexity, such as confined electric fields, that cannot be realized in a single heterojunction. In this work, we explore the properties of SrTiO 3–LaCrO 3 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 inmore » each layer of the superlattice, we correlate different types of defects with the associated materials properties of the superlattice. In conclusion, 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.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [3] ;  [4] ; ORCiD logo [4] ;  [2] ;  [3] ;  [2] ;  [2]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Auburn Univ., AL (United States). Dept. of Physics
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  3. SuperSTEM, Daresbury (United Kingdom). SciTech Daresbury Campus
  4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Publication Date:
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 29; Journal Issue: 3; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICS AND COMPUTING; 36 MATERIALS SCIENCE; Complex oxides; superlattices; x-ray photoelectron spectroscopy; x-ray absorption spectroscopy; scanning transmission electron microscopy
OSTI Identifier:
1340608

Comes, Ryan B., Spurgeon, Steven R., Kepaptsoglou, Despoina M., Engelhard, Mark H., Perea, Daniel E., Kaspar, Tiffany C., Ramasse, Quentin M., Sushko, Peter V., and Chambers, Scott A.. Probing the Origin of Interfacial Carriers in SrTiO3$-$LaCrO3 Superlattices. United States: N. p., Web. doi:10.1021/acs.chemmater.6b04329.
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.. Probing the Origin of Interfacial Carriers in SrTiO3$-$LaCrO3 Superlattices. United States. doi:10.1021/acs.chemmater.6b04329.
Comes, Ryan B., Spurgeon, Steven R., Kepaptsoglou, Despoina M., Engelhard, Mark H., Perea, Daniel E., Kaspar, Tiffany C., Ramasse, Quentin M., Sushko, Peter V., and Chambers, Scott A.. 2017. "Probing the Origin of Interfacial Carriers in SrTiO3$-$LaCrO3 Superlattices". United States. doi:10.1021/acs.chemmater.6b04329. https://www.osti.gov/servlets/purl/1340608.
@article{osti_1340608,
title = {Probing the Origin of Interfacial Carriers in SrTiO3$-$LaCrO3 Superlattices},
author = {Comes, Ryan B. and Spurgeon, Steven R. and Kepaptsoglou, Despoina M. and Engelhard, Mark H. and Perea, Daniel E. and Kaspar, Tiffany C. and Ramasse, Quentin M. and Sushko, Peter V. and Chambers, Scott A.},
abstractNote = {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. These repeating interfaces present an untapped opportunity to introduce an additional degree of complexity, such as confined electric fields, that cannot be realized 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. In conclusion, 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.},
doi = {10.1021/acs.chemmater.6b04329},
journal = {Chemistry of Materials},
number = 3,
volume = 29,
place = {United States},
year = {2017},
month = {1}
}