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This content will become publicly available on July 18, 2017

Title: Towards spin-polarized two-dimensional electron gas at a surface of an antiferromagnetic insulating oxide

Here, the surfaces of transition-metal oxides with the perovskite structure are fertile grounds for the discovery of novel electronic and magnetic phenomena. In this article, we combine scanning transmission electron microscopy (STEM) with density functional theory (DFT) calculations to obtain the electronic and magnetic properties of the (001) surface of a (LaFeO3)8/(SrFeO3)1 superlattice film capped with four layers of LaFeO3. Simultaneously acquired STEM images and electron-energy-loss spectra reveal the surface structure and a reduction in the oxidation state of iron from Fe3+ in the bulk to Fe2+ at the surface, extending over several atomic layers, which signals the presence of oxygen vacancies. The DFT calculations confirm the reduction in terms of oxygen vacancies and further demonstrate the stabilization of an exotic phase in which the surface layer is half metallic and ferromagnetic, while the bulk remains antiferromagnetic and insulating. Based on the calculations, we predict that the surface magnetism and conductivity can be controlled by tuning the partial pressure of oxygen.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [3] ;  [6] ;  [6] ;  [7] ;  [3]
  1. Vanderbilt Univ., Nashville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Washington Univ., St. Louis, MO (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Institute for Basic Science (IBS), Suwon (Republic of Korea); Sungkyunkwan Univ., (SKKU), Suwon (Republic of Korea)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Washington Univ., St. Louis, MO (United States)
  5. Argonne National Lab. (ANL), Argonne, IL (United States); Korea Institute of Science and Technology, Seoul (Republic of Korea)
  6. Argonne National Lab. (ANL), Argonne, IL (United States)
  7. Vanderbilt Univ., Nashville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
1329163
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 4; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY