Determination of formation energies and phase diagrams of transition metal oxides with DFT+U
| Autor: | Christian Elsässer, Daniel F. Urban, Daniel Mutter |
|---|---|
| Přispěvatelé: | Publica |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Work (thermodynamics)
Materials science general_materials_science materials modeling Iron oxide Oxide Thermodynamics transition metal oxide lcsh:Technology Article chemistry.chemical_compound Atomic orbital Transition metal Molecule transition metal oxides materials modelling lcsh:Microscopy density functional theory lcsh:QC120-168.85 Phase diagram lcsh:QH201-278.5 lcsh:T phase diagram chemistry lcsh:TA1-2040 lcsh:Descriptive and experimental mechanics Density functional theory lcsh:Electrical engineering. Electronics. Nuclear engineering lcsh:Engineering (General). Civil engineering (General) lcsh:TK1-9971 phase diagrams DFT+U |
| Zdroj: | Materials Materials, Vol 13, Iss 4303, p 4303 (2020) |
| Popis: | Knowledge about the formation energies of compounds is essential to derive phase diagrams of multicomponent phases with respect to elemental reservoirs. The determination of formation energies using common (semi-)local exchange-correlation approximations of the density functional theory (DFT) exhibits well-known systematic errors if applied to oxide compounds containing transition metal elements. In this work, we generalize, reevaluate, and discuss a set of approaches proposed and widely applied in the literature to correct for errors arising from the over-binding of the O2 molecule and from correlation effects of electrons in localized transition-metal orbitals. The DFT+U method is exemplarily applied to iron oxide compounds, and a procedure is presented to obtain the U values, which lead to formation energies and electronic band gaps comparable to the experimental values. Using such corrected formation energies, we derive the phase diagrams for LaFeO3, Li5FeO4, and NaFeO2, which are promising materials for energy conversion and storage devices. A scheme is presented to transform the variables of the phase diagrams from the chemical potentials of elemental phases to those of precursor compounds of a solid-state reaction, which represents the experimental synthesis process more appropriately. The discussed workflow of the methods can directly be applied to other transition metal oxides. |
| Databáze: | OpenAIRE |
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