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Electrostatic potential and valence modulation in La 0.7 Sr 0.3 MnO 3 thin films.
- Source :
-
Scientific reports [Sci Rep] 2018 Sep 25; Vol. 8 (1), pp. 14313. Date of Electronic Publication: 2018 Sep 25. - Publication Year :
- 2018
-
Abstract
- The Mn valence in thin film La <subscript>0.7</subscript> Sr <subscript>0.3</subscript> MnO <subscript>3</subscript> was studied as a function of film thickness in the range of 1-16 unit cells with a combination of non-destructive bulk and surface sensitive X-ray absorption spectroscopy techniques. Using a layer-by-layer valence model, it was found that while the bulk averaged valence hovers around its expected value of 3.3, a significant deviation occurs within several unit cells of the surface and interface. These results were supported by first principles calculations. The surface valence increases to up to Mn <superscript>3.7+</superscript> , whereas the interface valence reduces down to Mn <superscript>2.5+</superscript> . The change in valence from the expected bulk value is consistent with charge redistribution due to the polar discontinuity at the film-substrate interface. The comparison with theory employed here illustrates how this layer-by-layer valence evolves with film thickness and allows for a deeper understanding of the microscopic mechanisms at play in this effect. These results offer insight on how the two-dimensional electron gas is created in thin film oxide alloys and how the magnetic ordering is reduced with dimensionality.
Details
- Language :
- English
- ISSN :
- 2045-2322
- Volume :
- 8
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Scientific reports
- Publication Type :
- Academic Journal
- Accession number :
- 30254275
- Full Text :
- https://doi.org/10.1038/s41598-018-32701-x