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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: Talk

Thursday, February 28, 2008, 16:15–16:30, A 053

Understanding correlations in vanadium dioxide from first principles — •Matteo Gatti^1,2, Fabien Bruneval^1,2,3, Valerio Olevano^1,4, and Lucia Reining^1,2 — 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.