Assessment of Strain-Generated Oxygen Vacancies Using SrTiO3 Bicrystals

Si Young Choi, Sung Dae Kim, Minseok Choi, Hak Sung Lee, Jungho Ryu, Naoya Shibata, Teruyasu Mizoguchi, Eita Tochigi, Takahisa Yamamoto, Suk Joong L. Kang, Yuichi Ikuhara

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)

Abstract

Atomic-scale defects strongly influence the electrical and optical properties of materials, and their impact can be more pronounced in localized dimensions. Here, we directly demonstrate that strain triggers the formation of oxygen vacancies in complex oxides by examining the tilt boundary of SrTiO3 bicrystals. Through transmission electron microscopy and electron energy loss spectroscopy, we identify strains along the tilt boundary and oxygen vacancies in the strain-imposed regions between dislocation cores. First-principles calculations support that strains, irrespective of their type or sign, lower the formation energy of oxygen vacancies, thereby enhancing vacancy formation. Finally, current-voltage measurements confirm that such oxygen vacancies at the strained boundary result in a decrease of the nonlinearity of the I-V curve as well as the resistivity. Our results strongly indicate that oxygen vacancies are preferentially formed and are segregated at the regions where strains accumulate, such as heterogeneous interfaces and grain boundaries. (Graph Presented).

Original languageEnglish
Pages (from-to)4129-4134
Number of pages6
JournalNano Letters
Volume15
Issue number6
DOIs
Publication statusPublished - 2015 Jun 10
Externally publishedYes

Keywords

  • Perovskites
  • bicrystals
  • oxygen vacancies
  • strain engineering

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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