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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Tuning the electronic structure of SrTiO{sub 3}/SrFeO{sub 3−x} superlattices via composition and vacancy control

Using density functional theory-based calculations, we explore the effects of oxygen vacancies and epitaxial layering on the atomic, magnetic, and electronic structure of (SrTiO{sub 3}){sub n}(SrFeO{sub 3−x}){sub 1} superlattices. While structures without oxygen vacancies (x = 0) possess small or non-existent band gaps and ferromagnetic ordering in their iron layers, those with large vacancy concentrations (x = 0.5) have much larger gaps and antiferromagnetic ordering. Though the computed gaps depend numerically on the delicate energetic balance of vacancy ordering and on the value of Hubbard U{sub eff} used in the calculations, we demonstrate that changes in layering can tune the band gaps of these superlattices below that of SrTiO{sub 3} (3.2 eV) by raising their valence band maxima. This suggests the possibility that these superlattices could absorb in the solar spectrum, and could serve as water-splitting photocatalysts.

36 MATERIALS SCIENCE↗