Electrostatic potential and valence modulation in La0.7Sr0.3MnO3 thin films

Authors

Robbyn Trappen, West Virginia University
A. C. Garcia- Castro, West Virginia University
VU Thanh Tra, National Chiao Tung University
Chih-Yeh Huang, West Virginia University
Wilfredo Ibarra-Hernandez, West Virginia University
James Fitch, North Carolina State University
Sobhit Singh, West Virginia University
Jingling Zhou, West Virginia University
Guerau Cabrera, West Virginia University
Ying-Hao Chu, National Chiao Tung University
James M. LeBeau, North Carolina State University
Aldo H. Romero, West Virginia University
Mikel B. Holcomb, West Virginia UniversityFollow

Author ORCID Identifier

https://orcid.org/0000-0002-2676-483X

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https://orcid.org/0000-0002-5292-4235

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https://orcid.org/0000-0001-5968-0571

https://orcid.org/0000-0003-2111-3410

Document Type

Article

Publication Date

2018

College/Unit

Eberly College of Arts and Sciences

Department/Program/Center

Physics and Astronomy

Abstract

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.

Digital Commons Citation

Trappen, Robbyn; Garcia- Castro, A. C.; Tra, VU Thanh; Huang, Chih-Yeh; Ibarra-Hernandez, Wilfredo; Fitch, James; Singh, Sobhit; Zhou, Jingling; Cabrera, Guerau; Chu, Ying-Hao; LeBeau, James M.; Romero, Aldo H.; and Holcomb, Mikel B., "Electrostatic potential and valence modulation in La0.7Sr0.3MnO3 thin films" (2018). Faculty & Staff Scholarship. 1359.
https://researchrepository.wvu.edu/faculty_publications/1359

Source Citation

Trappen, R., Garcia-Castro, A. C., Tra, V. T., Huang, C.-Y., Ibarra-Hernandez, W., Fitch, J., … Holcomb, M. B. (2018). Electrostatic potential and valence modulation in La0.7Sr0.3MnO3 thin films. Scientific Reports, 8(1). https://doi.org/10.1038/s41598-018-32701-x

Comments

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