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Title: Optical Absorption and Band Gap Reduction in (Fe 1–x Cr x ) 2 O 3 Solid Solutions: A First-Principles Study

We provide a detailed theoretical analysis of the character of optical transitions and band gap reduction in (Fe1-xCrx)2O3 solid solutions using extensive periodic model and embedded cluster calculations. Optical absorption bands for x = 0.0, 0.5, and 1.0 are assigned on the basis of timedependent density functional theory (TDDFT) calculations. A band-gap reduction of as much as 0.7 eV with respect to that of pure α-Fe2O3 is found. This result can be attributed to predominantly two effects: (i) the higher valence band edge for x ≈ 0.5, as compared to those in pure α-Fe2O3 and α-Cr2O3, and, (ii) the appearance of Cr α Fe d–d transitions in the solid solutions. Broadening of the valence band due to hybridization of the O 2p states with Fe and Cr 3d states also contributes to band gap reduction.
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Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1932-7447; 44701; KC0304030
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. C; Journal Volume: 117; Journal Issue: 48
American Chemical Society
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
36 MATERIALS SCIENCE Environmental Molecular Sciences Laboratory