Electronic and optical properties of vanadium oxides from first principles
| Autor: | Z.T.Y. Liu, Sanjay V. Khare, Pankaj Sarin, N.J. Szymanski, T. Alderson, N.J. Podraza |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
General Computer Science Band gap General Physics and Astronomy Vanadium chemistry.chemical_element 02 engineering and technology General Chemistry Dielectric 021001 nanoscience & nanotechnology 01 natural sciences Molecular physics Optical conductivity Vanadium oxide Hybrid functional Computational Mathematics Transition metal chemistry Mechanics of Materials 0103 physical sciences Condensed Matter::Strongly Correlated Electrons General Materials Science Density functional theory 010306 general physics 0210 nano-technology |
| Zdroj: | Computational Materials Science. 146:310-318 |
| ISSN: | 0927-0256 |
| DOI: | 10.1016/j.commatsci.2018.01.048 |
| Popis: | We have studied the structural, energetic, electronic, and optical properties of six compounds belonging to the system of vanadium oxides (VO2, V2O5, V2O3, V3O5, V4O7, and V6O13), including both high- and low-temperature phases, obtained using first principles calculations based on density functional theory. The optimized structure of each compound is found to display strong octahedral distortion. This has a major impact on the electronic structures, causing strong mixing of t2g and eg orbitals. The electronic density of states was calculated with hybrid HSE06 functionals and the GGA + U method. The results show that the HSE06 functionals provide band gap values consistent with available experimental data. For the high-temperature phase of V2O5, we predict a band gap of 2.32 eV. Charge transfer is shown to decrease monotonically as a function of V-O ratio for all compounds. Complex dielectric functions, as computed with hybrid functionals and the GGA + U method, are reported. Hybrid functionals overestimate the energies at which absorption peaks occur, indicating strong electron-hole interaction and lattice polarization within the system. The computed optical conductivity, as derived from optical properties found with the GGA + U method, is in good quantitative agreement with available experimental data. The theoretical framework developed is applicable for other vanadium oxide phases and similar transition metal oxides. |
| Databáze: | OpenAIRE |
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