Berlin 2008 – wissenschaftliches Programm
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SYEC: Symposium Exact-exchange and hybrid functionals meet quasiparticle energy calculations
SYEC 2: Exact-exchange and hybrid functionals meet quasiparticle energy calculations II
SYEC 2.10: Vortrag
Donnerstag, 28. Februar 2008, 16:15–16:30, A 053
Understanding correlations in vanadium dioxide from first principles — •Matteo Gatti1,2, Fabien Bruneval1,2,3, Valerio Olevano1,4, and Lucia Reining1,2 — 1European Theoretical Spectrocopy Facility (ETSF) — 2LSI - Ecole Polytechnique, Palaiseau, France — 3Dep. of Chemistry and Applied Biosciences, ETH Zurich, Lugano, Switzerland — 4Institut Néel, CNRS, Grenoble, France
Vanadium dioxide is a prototype material for the discussion of correlation effects in solids. First-principles density-functional theory does not describe the metal-insulator transition, whereas strongly correlated models reproduce the main features. Here we present a parameter-free GW calculation of VO2 and show that correlation effects in the bandstructure of both the metallic and the insulating phases are correctly reproduced, provided that quasiparticle energies and wavefunctions are calculated self-consistently. Our calculations explain the satellite in the photoemission spectrum of the metal as due to a plasmon resonance in the energy-loss function and show that this feature disappears in the insulator.