Journal Article

FZJ-2019-00554

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Electronic structure of negative charge transfer CaFeO 3 across the metal-insulator transition

Rogge, P. C. ; Chandrasena, R. U. ; Cammarata, A. ; Green, R. J. ; Shafer, P. ; Lefler, B. M. ; Huon, A. ; Arab, A. ; Arenholz, E. ; Lee, H. N. ; Lee, T.-L. ; Nemsak, S. (Corresponding author)FZJ* ; Rondinelli, J. M. ; Gray, A. X. ; May, S. J. (Corresponding author)

2018
APS College Park, MD

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Please use a persistent id in citations: http://hdl.handle.net/2128/21329  doi:10.1103/PhysRevMaterials.2.015002

Abstract: We investigated the metal-insulator transition for epitaxial thin films of the perovskite CaFeO3, a material with a significant oxygen ligand hole contribution to its electronic structure. We find that biaxial tensile and compressive strain suppress the metal-insulator transition temperature. By combining hard x-ray photoelectron spectroscopy, soft x-ray absorption spectroscopy, and density functional calculations, we resolve the element-specific changes to the electronic structure across the metal-insulator transition. We demonstrate that the Fe sites undergo no observable spectroscopic change between the metallic and insulating states, whereas the O electronic configuration undergoes significant changes. This strongly supports the bond-disproportionation model of the metal-insulator transition for CaFeO3 and highlights the importance of ligand holes in its electronic structure. By sensitively measuring the ligand hole density, however, we find that it increases by ∼5–10% in the insulating state, which we ascribe to a further localization of electron charge on the Fe sites. These results provide detailed insight into the metal-insulator transition of negative charge transfer compounds and should prove instructive for understanding metal-insulator transitions in other late transition metal compounds such as the nickelates.

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Contributing Institute(s):

1. Elektronische Eigenschaften (PGI-6)

Research Program(s):

1. 522 - Controlling Spin-Based Phenomena (POF3-522) (POF3-522)

Appears in the scientific report 2018

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; Science Citation Index Expanded ; Web of Science Core Collection

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