Dresden 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 64: Focussed session: Theory and computation of electronic structure: new frontiers V (jointly with HL, DS)
O 64.6: Vortrag
Donnerstag, 17. März 2011, 12:45–13:00, TRE Phy
The surprising accuracy of semilocal functionals within density functional theory (DFT): A study of systems involving point defects — •Rampi Ramprasad1, Patrick Rinke2, and Matthias Scheffler2 — 1University of Connecticut, Storrs, USA; Fritz-Haber-Institut der MPG, Berlin, Germany — 2Fritz-Haber-Institut der MPG, Berlin, Germany
The use of screened nonlocal exchange functionals within hybrid DFT computations is becoming practical, providing improved electronic structure descriptions [1]. However, the appropriate amount of nonlocal exchange (α) and the extent of screening (ω) to be used are still being explored. Here, we will focus on two properties relevant for systems containing point defects: charge transition levels and defect formation energies. By making the α and ω as variables, it will be shown that semilocal treatments of the exchange interaction for defects in Si and ZrO2 yield charge transition levels that are quantitatively competitive with more involved nonlocal treatments, extending notions presented recently [2]. This implies that the difference in formation energies of neutral and charged defects remains a constant, although the formation energy itself may vary with the type of treatment. We have identified correlations between defect formation energies and features of the electronic structure of the defect-free parent material, allowing for extrapolations of the formation energy to the “correct“ values.
[1] A. V. Krukau, et al, J. Chem. Phys. 125, 224106 (2006). [2] H. Komsa, et al, Phys. Rev. B 81, 205118 (2010).