Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 74: Focussed Session: Frontiers of Electronic Structure Theory VII (jointly with HL and TT)
O 74.2: Vortrag
Donnerstag, 14. März 2013, 16:15–16:30, H36
Restoring piecewise linearity in density-functional theory — •Ismaila Dabo1, Andrea Ferretti2, Matteo Cococcioni3, and Nicola Marzari4 — 1Ecole des Ponts ParisTech, Marne-la-Vallee, France — 2CNR-Istituto Nanoscienze, Modena, Italy — 3University of Minnesota, Minneapolis, USA — 4EPFL, Lausanne, USA
Electronic-structure calculations based upon density-functional theory (DFT) have been fruitful in diverse areas of condensed matter physics. Despite their exceptional success, it can hardly be denied that a range of fundamental electronic properties fall beyond the scope of current DFT approximations. Many of the failures of DFT calculations take root in the lack of piecewise linearity of approximate functionals, which reverberates negatively on the electronic-structure description of systems involving fractionally occupied and spatially delocalized electronic states, including but not restricted to dissociated molecules, adsorbed species, charge-transfer complexes, and semiconducting compounds. In this talk, I will present a novel class of first-principles methods that restores the piecewise linearity of the total energy by imposing Koopmans' theorem to DFT approximations. The Koopmans-compliant approach is apt at describing full orbital spectra within a few tenths of an electron-volt relative to experimental direct and inverse photoemission data. This level of accuracy is comparable to the predictive performance of accurate many-body perturbation theory methods at a fraction of their computational cost, and with the additional benefit of providing accurate total energies for systems with fractional occupations.