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Title: Dynamic interface rearrangement in LaFeO 3 / n - SrTiO 3 heterojunctions

Abstract

Thin-film synthesis methods that have developed over the past decades have unlocked emergent interface properties ranging from conductivity to ferroelectricity. However, our attempts to exercise precise control over interfaces are constrained by a limited understanding of growth pathways and kinetics. In this paper, we demonstrate that shuttered molecular beam epitaxy induces rearrangements of atomic planes at a polar/nonpolar junction of LaFeO 3 (LFO)/n-SrTiO 3 (STO) depending on the substrate termination. Surface characterization confirms that substrates with two different (TiO 2 and SrO) terminations were prepared prior to LFO deposition; however, local electron-energy-loss spectroscopy measurements of the final heterojunctions show a predominantly LaO/TiO 2 interfacial junction in both cases. Ab initio simulations suggest that the interfaces can be stabilized by trapping extra oxygen (in LaO/TiO 2) and forming oxygen vacancies (in FeO 2/SrO), which points to different growth kinetics in each case and may explain the apparent disappearance of the FeO 2/SrO interface. Finally, we conclude that judicious control of deposition time scales can be used to modify growth pathways, opening new avenues to control the structure and properties of interfacial systems.

Authors:
 [1];  [1];  [1];  [2]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical and Computational Sciences Directorate
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical and Computational Sciences Directorate; Auburn Univ., AL (United States). Dept. of Physics
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); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); PNNL Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1430717
Alternate Identifier(s):
OSTI ID: 1407448
Report Number(s):
PNNL-SA-127972
Journal ID: ISSN 2475-9953
Grant/Contract Number:
AC05-76RL01830; PN13100/2581
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review Materials
Additional Journal Information:
Journal Volume: 1; Journal Issue: 6; Journal ID: ISSN 2475-9953
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; composition; crystal phenomena; defects; growth; surface & interfacial phenomena; thin films; density functional theory; electron energy loss spectroscopy; molecular beam epitaxy; scanning transmission electron microscopy

Citation Formats

Spurgeon, Steven R., Sushko, Peter V., Chambers, Scott A., and Comes, Ryan B. Dynamic interface rearrangement in LaFeO3/n-SrTiO3 heterojunctions. United States: N. p., 2017. Web. doi:10.1103/PhysRevMaterials.1.063401.
Spurgeon, Steven R., Sushko, Peter V., Chambers, Scott A., & Comes, Ryan B. Dynamic interface rearrangement in LaFeO3/n-SrTiO3 heterojunctions. United States. doi:10.1103/PhysRevMaterials.1.063401.
Spurgeon, Steven R., Sushko, Peter V., Chambers, Scott A., and Comes, Ryan B. Mon . "Dynamic interface rearrangement in LaFeO3/n-SrTiO3 heterojunctions". United States. doi:10.1103/PhysRevMaterials.1.063401.
@article{osti_1430717,
title = {Dynamic interface rearrangement in LaFeO3/n-SrTiO3 heterojunctions},
author = {Spurgeon, Steven R. and Sushko, Peter V. and Chambers, Scott A. and Comes, Ryan B.},
abstractNote = {Thin-film synthesis methods that have developed over the past decades have unlocked emergent interface properties ranging from conductivity to ferroelectricity. However, our attempts to exercise precise control over interfaces are constrained by a limited understanding of growth pathways and kinetics. In this paper, we demonstrate that shuttered molecular beam epitaxy induces rearrangements of atomic planes at a polar/nonpolar junction of LaFeO3 (LFO)/n-SrTiO3 (STO) depending on the substrate termination. Surface characterization confirms that substrates with two different (TiO2 and SrO) terminations were prepared prior to LFO deposition; however, local electron-energy-loss spectroscopy measurements of the final heterojunctions show a predominantly LaO/TiO2 interfacial junction in both cases. Ab initio simulations suggest that the interfaces can be stabilized by trapping extra oxygen (in LaO/TiO2) and forming oxygen vacancies (in FeO2/SrO), which points to different growth kinetics in each case and may explain the apparent disappearance of the FeO2/SrO interface. Finally, we conclude that judicious control of deposition time scales can be used to modify growth pathways, opening new avenues to control the structure and properties of interfacial systems.},
doi = {10.1103/PhysRevMaterials.1.063401},
journal = {Physical Review Materials},
number = 6,
volume = 1,
place = {United States},
year = {Mon Nov 06 00:00:00 EST 2017},
month = {Mon Nov 06 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on November 6, 2018
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