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Title: In-situ probing of coupled atomic restructuring and metallicity of oxide heterointerfaces induced by polar adsorbates

Abstract

Microscopic understanding of the surface-controlled conductivity of the two dimensional electron gas at complex oxide interfaces is crucial for developing functional interfaces. We observe conductivity and structural modification using in-situ synchrotron surface x-ray diffraction as the surface of a model LaAlO3/SrTiO3 (001) heterostructure is changed by polar adsorbates. We find that polar adsorbate-induced interfacial metallicity reduces polar distortions in the LaAlO3 layer. First-principles density functional theory calculations show that surface dipoles introduced by polar adsorbates lead to additional charge transfer and the reduction of polar displacements in the LaAlO3 layer, consistent with the experimental observations. Our study supports that internal structural deformations controlling functionalities can be driven without the application of direct electrical or thermal bias and offers a route to tuning interfacial properties. These results also highlight the important role of in-situ x-ray scattering with atomic resolution in capturing and exploring structural distortions and charge density changes caused by external perturbations such as chemical adsorption, redox reaction, and generation and/or annihilation of surface defects.

Authors:
ORCiD logo [1];  [2];  [3]; ORCiD logo [4]; ORCiD logo [1];  [1];  [1];  [1];  [5];  [4];  [3];  [1]
  1. Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
  2. X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
  3. Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588, USA
  4. Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
  5. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
National Science Foundation (NSF); Air Force Research Laboratory (AFRL) - Air Force Office of Scientific Research (AFOSR); USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division
OSTI Identifier:
1418361
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 111; Journal Issue: 14
Country of Publication:
United States
Language:
English
Subject:
Adsorption; Chemical compounds; Heterointerfaces; Heterojunctions; Synchrotrons

Citation Formats

Ryu, S., Zhou, H., Paudel, T. R., Irwin, J., Podkaminer, J. P., Bark, C. W., Lee, D., Kim, T. H., Fong, D. D., Rzchowski, M. S., Tsymbal, E. Y., and Eom, C. B. In-situ probing of coupled atomic restructuring and metallicity of oxide heterointerfaces induced by polar adsorbates. United States: N. p., 2017. Web. doi:10.1063/1.4991956.
Ryu, S., Zhou, H., Paudel, T. R., Irwin, J., Podkaminer, J. P., Bark, C. W., Lee, D., Kim, T. H., Fong, D. D., Rzchowski, M. S., Tsymbal, E. Y., & Eom, C. B. In-situ probing of coupled atomic restructuring and metallicity of oxide heterointerfaces induced by polar adsorbates. United States. doi:10.1063/1.4991956.
Ryu, S., Zhou, H., Paudel, T. R., Irwin, J., Podkaminer, J. P., Bark, C. W., Lee, D., Kim, T. H., Fong, D. D., Rzchowski, M. S., Tsymbal, E. Y., and Eom, C. B. Mon . "In-situ probing of coupled atomic restructuring and metallicity of oxide heterointerfaces induced by polar adsorbates". United States. doi:10.1063/1.4991956.
@article{osti_1418361,
title = {In-situ probing of coupled atomic restructuring and metallicity of oxide heterointerfaces induced by polar adsorbates},
author = {Ryu, S. and Zhou, H. and Paudel, T. R. and Irwin, J. and Podkaminer, J. P. and Bark, C. W. and Lee, D. and Kim, T. H. and Fong, D. D. and Rzchowski, M. S. and Tsymbal, E. Y. and Eom, C. B.},
abstractNote = {Microscopic understanding of the surface-controlled conductivity of the two dimensional electron gas at complex oxide interfaces is crucial for developing functional interfaces. We observe conductivity and structural modification using in-situ synchrotron surface x-ray diffraction as the surface of a model LaAlO3/SrTiO3 (001) heterostructure is changed by polar adsorbates. We find that polar adsorbate-induced interfacial metallicity reduces polar distortions in the LaAlO3 layer. First-principles density functional theory calculations show that surface dipoles introduced by polar adsorbates lead to additional charge transfer and the reduction of polar displacements in the LaAlO3 layer, consistent with the experimental observations. Our study supports that internal structural deformations controlling functionalities can be driven without the application of direct electrical or thermal bias and offers a route to tuning interfacial properties. These results also highlight the important role of in-situ x-ray scattering with atomic resolution in capturing and exploring structural distortions and charge density changes caused by external perturbations such as chemical adsorption, redox reaction, and generation and/or annihilation of surface defects.},
doi = {10.1063/1.4991956},
journal = {Applied Physics Letters},
number = 14,
volume = 111,
place = {United States},
year = {Mon Oct 02 00:00:00 EDT 2017},
month = {Mon Oct 02 00:00:00 EDT 2017}
}