The role of isotropic and anisotropic Hubbard corrections for the magnetic ordering and absolute band alignment of hematite α-Fe<inf>2</inf>O<inf>3</inf>(0001) surfaces



Bandaru, S, Scivetti, I, Yam, CY and Teobaldi, G ORCID: 0000-0001-6068-6786
(2019) The role of isotropic and anisotropic Hubbard corrections for the magnetic ordering and absolute band alignment of hematite α-Fe<inf>2</inf>O<inf>3</inf>(0001) surfaces. Progress in Natural Science: Materials International.

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Abstract

© 2019 Chinese Materials Research Society The isotropic (+U) and anisotropic [+(U−J)] corrected Density Functional Theory study for bulk hematite (α-Fe2O3) was carried out, and several competing terminations of its (0001) surface modeled via slabs of increasing thickness from twelve to thirty-six Fe-layers. In spite of small quantitative differences, the use of either U or (U-J) corrections showed not to qualitatively affect the results of the simulations both for bulk α-Fe2O3 and the lowest-energy α-Fe2O3(0001) surface studied, regardless of the thickness of the slab used. The energy favored antiferromagnetic ordering of bulk α-Fe2O3 was preserved in the relaxed slabs, with the largest surface-induced effects limited to the topmost three Fe-layers in the slabs. Mixed O- and Fe-terminations were calculated to be energetically favored and insulating. Conversely, fully O- or Fe-terminated surfaces were calculated to be energetically disfavored and with metallic states. Finally, the role of Fe- or O- termination for the semiconducting or metallic nature as well as absolute band alignment of α-Fe2O3(0001) surfaces was analyzed and discussed with respect to the challenges in enhancing the activity of α-Fe2O3 samples as photo-electrode for water splitting.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 14 Aug 2019 08:57
Last Modified: 21 Jun 2021 15:10
DOI: 10.1016/j.pnsc.2019.05.010
Open Access URL: http://doi.org/10.1016/j.pnsc.2019.05.010
URI: https://livrepository.liverpool.ac.uk/id/eprint/3051701