S. L. Dudarev
Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
G. A. Botton
Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom
S. Y. Savraso
v Max-Planck-Institut fu¨r Festko¨perforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
C. J. Humphreys
Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom A. P. Sutton Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom ~Received 23 June 1997!
Abstract:
We demonstrate how by taking better account of electron correlations in the 3d shell of metal ions in nickel oxide it is possible to improve the description of both electron energy loss spectra and parameters characterizing the structural stability of the material compared with local spin density functional theory.
To download the article click on the link below:
https://www.researchgate.net/profile/Sergei_Dudarev/publication/220037632_Electron-energy-loss_spectra_and_the_structural_stability_of_nickel_oxide_An_LSDAU_study/links/0fcfd508fae8d77113000000.pdf
I. INTRODUCTION
In recent years substantial progress has been achieved in the development of accurate ab initio approaches to calculating the physical properties of various compounds, and in some cases it is now easier to predict the structure of a new material theoretically than to make it in a laboratory.1 For many metals, semiconductors and insulators the local spin density approximation ~LSDA! to the density functional theory ~DFT! is known to provide a reliable variational description of the ground state of the electronic structure of the solid.2,3 At the same time there are cases where applications of the DFT-LSDA have been far less successful. In particular, difficulties arise when a conventional DFT-LSDA approach is applied to the treatment of the electronic structure of the material where some of the ions contain partly filled valence d or f shells. It was shown by Terakura et al.4 that for many of the transition metal oxides the DFT-LSDA predicts metallic ground states instead of experimentally observed insulating ones. If antiferromagnetic order is taken into account, the DFT-LSDA treatment may lead to an insulating state but the forbidden gap still turns out to be an order of magnitude smaller than that observed using electron spectroscopy.5 The origin of the failure of the DFT-LSDA in transition metal oxides is known to be associated with an inadequate description of the strong Coulomb repulsion between 3d electrons localized on metal ions.6 Uranium dioxide represents a similar example of a compound where uranium ions contain partly filled f shells and where all of the known LSDA solutions favor metallic conductivity.7 Experimentally UO2 is known to be a good insulator,8 and to explain the origin of the insulating ground state, it is necessary to go beyond the LSDA.9 In addition to making incorrect predictions regarding the nature of the ground state of transition metal and actinide oxides quoted above, the DFTLSDA systematically underestimates their equilibrium lattice constants10 and overestimates binding energies, raising questions about the applicability of this approach to making predictions about equilibrium configurations of surface and defect structures.
Abstract:
We demonstrate how by taking better account of electron correlations in the 3d shell of metal ions in nickel oxide it is possible to improve the description of both electron energy loss spectra and parameters characterizing the structural stability of the material compared with local spin density functional theory.
To download the article click on the link below:
https://www.researchgate.net/profile/Sergei_Dudarev/publication/220037632_Electron-energy-loss_spectra_and_the_structural_stability_of_nickel_oxide_An_LSDAU_study/links/0fcfd508fae8d77113000000.pdf
I. INTRODUCTION
In recent years substantial progress has been achieved in the development of accurate ab initio approaches to calculating the physical properties of various compounds, and in some cases it is now easier to predict the structure of a new material theoretically than to make it in a laboratory.1 For many metals, semiconductors and insulators the local spin density approximation ~LSDA! to the density functional theory ~DFT! is known to provide a reliable variational description of the ground state of the electronic structure of the solid.2,3 At the same time there are cases where applications of the DFT-LSDA have been far less successful. In particular, difficulties arise when a conventional DFT-LSDA approach is applied to the treatment of the electronic structure of the material where some of the ions contain partly filled valence d or f shells. It was shown by Terakura et al.4 that for many of the transition metal oxides the DFT-LSDA predicts metallic ground states instead of experimentally observed insulating ones. If antiferromagnetic order is taken into account, the DFT-LSDA treatment may lead to an insulating state but the forbidden gap still turns out to be an order of magnitude smaller than that observed using electron spectroscopy.5 The origin of the failure of the DFT-LSDA in transition metal oxides is known to be associated with an inadequate description of the strong Coulomb repulsion between 3d electrons localized on metal ions.6 Uranium dioxide represents a similar example of a compound where uranium ions contain partly filled f shells and where all of the known LSDA solutions favor metallic conductivity.7 Experimentally UO2 is known to be a good insulator,8 and to explain the origin of the insulating ground state, it is necessary to go beyond the LSDA.9 In addition to making incorrect predictions regarding the nature of the ground state of transition metal and actinide oxides quoted above, the DFTLSDA systematically underestimates their equilibrium lattice constants10 and overestimates binding energies, raising questions about the applicability of this approach to making predictions about equilibrium configurations of surface and defect structures.
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