標題: Electrostatic potential and valence modulation in La0.7Sr0.3MnO3 thin films
作者: Trappen, Robbyn
Garcia-Castro, A. C.
Vu Thanh Tra
Huang, Chih-Yeh
Ibarra-Hernandez, Wilfredo
Fitch, James
Singh, Sobhit
Zhou, Jinling
Cabrera, Guerau
Chu, Ying-Hao
LeBeau, James M.
Romero, Aldo H.
Holcomb, Mikel B.
物理研究所
Institute of Physics
公開日期: 25-九月-2018
摘要: The Mn valence in thin film La0.7Sr0.3MnO3 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 Mn3.7+, whereas the interface valence reduces down to Mn2.5+. 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.
URI: http://dx.doi.org/10.1038/s41598-018-32701-x
http://hdl.handle.net/11536/148211
ISSN: 2045-2322
DOI: 10.1038/s41598-018-32701-x
期刊: SCIENTIFIC REPORTS
Volume: 8
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