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Title: Direct observation of oxygen-vacancy-enhanced polarization in a SrTiO3-buffered ferroelectric BaTiO3 film on GaAs

The integration of functional oxide thin-films on compound semiconductors can lead to a class of reconfigurable spin-based optoelectronic devices if defect-free, fully reversible active layers are stabilized. However, previous first-principles calculations predicted that SrTiO3 thin filmsgrown on Si exhibit pinned ferroelectric behavior that is not switchable, due to the presence of interfacial vacancies. Meanwhile, piezoresponse force microscopy measurements have demonstrated ferroelectricity in BaTiO3 grown on semiconductor substrates. The presence of interfacial oxygen vacancies in such complex-oxide/semiconductor systems remains unexplored, and their effect on ferroelectricity is controversial. We also use a combination of aberration-corrected scanning transmission electron microscopy and first-principles density functional theory modeling to examine the role of interfacial oxygen vacancies on the ferroelectricpolarization of a BaTiO3 thin filmgrown on GaAs. Moreover, we demonstrate that interfacial oxygen vacancies enhance the polar discontinuity (and thus the single domain, out-of-plane polarization pinning in BaTiO3), and propose that the presence of surface charge screening allows the formation of switchable domains.
 [1] ;  [2] ;  [3] ;  [3] ;  [2] ;  [4] ;  [5] ;  [5]
  1. Univ. of Illinois, Chicago, IL (United States); Vanderbilt Univ., Nashville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Vanderbilt Univ., Nashville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Texas State Univ., San Marcos, TX (United States)
  4. National Univ. of Singapore (Singapore)
  5. Univ. of Illinois, Chicago, IL (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0003-6951; R&D Project: MA015MACA; KC0201010
Grant/Contract Number:
SC00112704; FG02-09ER46554, DE-AC02-05CH11231; AC05-00OR22725
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 107; Journal Issue: 20; Journal ID: ISSN 0003-6951
American Institute of Physics (AIP)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States