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Title: Dominance of Interface Chemistry over the Bulk Properties in Determining the Electronic Structure of Epitaxial Metal/Perovskite Oxide Heterojunctions

Abstract

We show that despite very similar crystallographic properties and work function values in the bulk, epitaxial Fe and Cr metallizations on Nb:SrTiO 3(001) generate completely different heterojunction electronic properties. Cr is Ohmic whereas Fe forms a Schottky barrier with a barrier height of 0.50 eV. This contrast arises because of differences in interface chemistry. In contrast to Cr [Chambers, S. A. et al., Adv. Mater. 2013, 25, 4001.], Fe exhibits a +2 oxidation state and occupies Ti sites in the perovskite lattice, resulting in negligible charge transfer to Ti, upward band bending, and Schottky barrier formation. The differences between Cr and Fe are understood by performing first-principles calculations of the energetics of defect formation which corroborate the observed interface chemistry and structure.

Authors:
; ; ; ;  [1];
  1. Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, United Kingdom
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1489005
Report Number(s):
PNNL-SA-108999
Journal ID: ISSN 0897-4756
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 27; Journal Issue: 11; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
epitaxial metal/perovskite oxide heterojunctions

Citation Formats

Chambers, Scott A., Du, Yingge, Gu, Meng, Droubay, Timothy C., Hepplestone, Steven P., and Sushko, Peter V. Dominance of Interface Chemistry over the Bulk Properties in Determining the Electronic Structure of Epitaxial Metal/Perovskite Oxide Heterojunctions. United States: N. p., 2015. Web. doi:10.1021/acs.chemmater.5b01118.
Chambers, Scott A., Du, Yingge, Gu, Meng, Droubay, Timothy C., Hepplestone, Steven P., & Sushko, Peter V. Dominance of Interface Chemistry over the Bulk Properties in Determining the Electronic Structure of Epitaxial Metal/Perovskite Oxide Heterojunctions. United States. doi:10.1021/acs.chemmater.5b01118.
Chambers, Scott A., Du, Yingge, Gu, Meng, Droubay, Timothy C., Hepplestone, Steven P., and Sushko, Peter V. Fri . "Dominance of Interface Chemistry over the Bulk Properties in Determining the Electronic Structure of Epitaxial Metal/Perovskite Oxide Heterojunctions". United States. doi:10.1021/acs.chemmater.5b01118.
@article{osti_1489005,
title = {Dominance of Interface Chemistry over the Bulk Properties in Determining the Electronic Structure of Epitaxial Metal/Perovskite Oxide Heterojunctions},
author = {Chambers, Scott A. and Du, Yingge and Gu, Meng and Droubay, Timothy C. and Hepplestone, Steven P. and Sushko, Peter V.},
abstractNote = {We show that despite very similar crystallographic properties and work function values in the bulk, epitaxial Fe and Cr metallizations on Nb:SrTiO3(001) generate completely different heterojunction electronic properties. Cr is Ohmic whereas Fe forms a Schottky barrier with a barrier height of 0.50 eV. This contrast arises because of differences in interface chemistry. In contrast to Cr [Chambers, S. A. et al., Adv. Mater. 2013, 25, 4001.], Fe exhibits a +2 oxidation state and occupies Ti sites in the perovskite lattice, resulting in negligible charge transfer to Ti, upward band bending, and Schottky barrier formation. The differences between Cr and Fe are understood by performing first-principles calculations of the energetics of defect formation which corroborate the observed interface chemistry and structure.},
doi = {10.1021/acs.chemmater.5b01118},
journal = {Chemistry of Materials},
issn = {0897-4756},
number = 11,
volume = 27,
place = {United States},
year = {2015},
month = {5}
}