Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 41: Focussed Session: Frontiers of Electronic Structure Theory IV (jointly with HL and TT)
O 41.5: Vortrag
Mittwoch, 13. März 2013, 11:45–12:00, H36
Magnetic Spectroscopies with DFT + Hubbard (U,V) — •Emine Kucukbenli1, Davide Ceresoli2, and Nicola Marzari1 — 1Theory and Simulation of Materials, École Polytechnique Fédérale de Lausanne (CH) — 2CNR-ISTM Institute of Molecular Science and Technology, Milan (IT)
Hubbard U corrections to exchange-correlation functionals, introduced to deal with correlated electrons, have been shown to greatly improve the accuracy of DFT calculations of transition-metals, thanks to their ability to restore piecewise linearity of energy as a function of occupations and thus correct self-interaction errors. In addition, U is not a fitting parameter but can be calculated ab initio, using linear-response (LR) formulations.
Nevertheless, transition-metal complexes that display both covalent and ionic character are poorly described by DFT+U. Recently, the addition of an intersite Hubbard V is suggested to restore the accuracy of DFT+U for these cases, while V can be obtained ab initio as well.
In this study we combine DFT+U+V with the gauge-invariant projector augmented wave (GIPAW) method, and calculate magnetic spectroscopic properties of systems with transition metals. We have been implementing this combination in Quantum ESPRESSO package, both for LR and the recently introduced converse approach, that uses a much simpler Berry-phase calculation of the orbital magnetization. We then examine the performance of U+V corrections in determining the structural properties and hyperfine interaction parameters of small transition-metal molecules and complex organometallic systems.