Momentum-dependent band spin splitting in semiconducting MnO2: a density functional calculation
Recently, manganese-oxide compounds have attracted considerable attention, in particular, as candidate materials for photochemical water-splitting reactions. Here, we investigate electronic states of pristine manganese dioxides (MnO2) in different crystal phases using spin-polarized density function...
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Published in | Physical chemistry chemical physics : PCCP Vol. 18; no. 19; pp. 13294 - 13303 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
England
11.05.2016
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Online Access | Get full text |
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Summary: | Recently, manganese-oxide compounds have attracted considerable attention, in particular, as candidate materials for photochemical water-splitting reactions. Here, we investigate electronic states of pristine manganese dioxides (MnO2) in different crystal phases using spin-polarized density functional theory (DFT) with Hubbard U correction. Geometrical structures and band dispersions of α-, β-, δ-, and λ-MnO2 crystals with collinear magnetic [ferromagnetic (FM) and antiferromagnetic (AFM)] orders are discussed in detail. We reveal that penalty energies that arise by violating the Goodenough-Kanamori rule are important and the origin of the magnetic interactions of the MnO2 crystals is governed by the superexchange interactions of Mn-O-Mn groups. In addition, it is found that momentum-dependent band spin splitting occurs in the AFM α-, β-, and δ-MnO2 crystals while no spin splitting occurs in the AFM λ-MnO2 crystal. Our results show that spin-split band dispersions stem from the different orientations of Mn-centred oxygen octahedra. Such interesting electronic states of the MnO2 crystals are unraveled by our discussion on the relationship between the effective (spin-dependent) single-electron potentials and the space-group symmetry operations that map up-spin Mn atoms onto down-spin Mn atoms. This work provides a basis to understand the relationship between the spin-dependent electronic states and the crystallography of manganese oxides. Another relationship to the recent experimental observations of the photochemical oxygen evolution of MnO2 crystals is also discussed. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1463-9084 |
DOI: | 10.1039/c5cp07806g |