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Title: Atomic and Electronic Structure of the Fe₃O₄ (111)/MgO(111) Model Polar Oxide Interface

Abstract

High resolution transmission electron microscopy (HRTEM) and density functional calculations are used to study the effect of interface polarity on the atomic and electronic structure of the prototype Fe?O?(111)/MgO(111) polar oxide interface. We show that atomically abrupt interfaces exist between the MgO(111)-substrate and magnetite(111) film in regions separated by Fe nanocrystals, and propose a solution for this oxide-oxide interface structure. Comparisons of through-focus/through-thickness experimental HRTEM images with calculated images for model interface structures suggest metal-oxygen-metal (i.e., Mg-O-Fe) interface bonding with octahedral (B) coordination of the first Fe monolayer, rather than the combination of tetrahedral-octahedral-tetrahedral (ABA) stacking also found in Fe?O?. First-principles calculations for all the different models find metal-induced gap states in the interface oxygen layer. Consistent with the HRTEM results, the MgO-Fe?O? interface stacking Mg/O/Mg/O/3FeB/O/FeAFeBFeA? is calculated to be the energetically most favorable, and effectively screening the MgO(111) substrate surface polarity. The data and calculations exclude mixing of Mg and Fe across the interface, in contrast to the commonly invoked mechanism of cation mixing at compound semiconductor polar interfaces.

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
876921
Report Number(s):
PNNL-SA-45276
13290; KP1303000; TRN: US200608%%2
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter; Journal Volume: 72; Journal Issue: 19
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; IRON OXIDES; MAGNESIUM OXIDES; MOLECULAR STRUCTURE; INTERFACES; ELECTRONIC STRUCTURE; Environmental Molecular Sciences Laboratory

Citation Formats

Lazarov, Vlado, Weinert, M, Chambers, Scott A., and Gajdardziska-josifovska, Marija. Atomic and Electronic Structure of the Fe₃O₄ (111)/MgO(111) Model Polar Oxide Interface. United States: N. p., 2005. Web. doi:10.1103/PhysRevB.72.195401.
Lazarov, Vlado, Weinert, M, Chambers, Scott A., & Gajdardziska-josifovska, Marija. Atomic and Electronic Structure of the Fe₃O₄ (111)/MgO(111) Model Polar Oxide Interface. United States. doi:10.1103/PhysRevB.72.195401.
Lazarov, Vlado, Weinert, M, Chambers, Scott A., and Gajdardziska-josifovska, Marija. Tue . "Atomic and Electronic Structure of the Fe₃O₄ (111)/MgO(111) Model Polar Oxide Interface". United States. doi:10.1103/PhysRevB.72.195401.
@article{osti_876921,
title = {Atomic and Electronic Structure of the Fe₃O₄ (111)/MgO(111) Model Polar Oxide Interface},
author = {Lazarov, Vlado and Weinert, M and Chambers, Scott A. and Gajdardziska-josifovska, Marija},
abstractNote = {High resolution transmission electron microscopy (HRTEM) and density functional calculations are used to study the effect of interface polarity on the atomic and electronic structure of the prototype Fe?O?(111)/MgO(111) polar oxide interface. We show that atomically abrupt interfaces exist between the MgO(111)-substrate and magnetite(111) film in regions separated by Fe nanocrystals, and propose a solution for this oxide-oxide interface structure. Comparisons of through-focus/through-thickness experimental HRTEM images with calculated images for model interface structures suggest metal-oxygen-metal (i.e., Mg-O-Fe) interface bonding with octahedral (B) coordination of the first Fe monolayer, rather than the combination of tetrahedral-octahedral-tetrahedral (ABA) stacking also found in Fe?O?. First-principles calculations for all the different models find metal-induced gap states in the interface oxygen layer. Consistent with the HRTEM results, the MgO-Fe?O? interface stacking Mg/O/Mg/O/3FeB/O/FeAFeBFeA? is calculated to be the energetically most favorable, and effectively screening the MgO(111) substrate surface polarity. The data and calculations exclude mixing of Mg and Fe across the interface, in contrast to the commonly invoked mechanism of cation mixing at compound semiconductor polar interfaces.},
doi = {10.1103/PhysRevB.72.195401},
journal = {Physical Review. B, Condensed Matter},
number = 19,
volume = 72,
place = {United States},
year = {Tue Nov 01 00:00:00 EST 2005},
month = {Tue Nov 01 00:00:00 EST 2005}
}
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