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SYEC: Symposium Exact-exchange and hybrid functionals meet quasiparticle energy calculations

SYEC 4: Exact-exchange and hybrid functionals meet quasiparticle energy calculations IV

SYEC 4.3: Vortrag

Freitag, 29. Februar 2008, 10:45–11:00, A 151

Total and self-energies beyond LDA and GGA: exact-exchange, GW and MP2 united by numeric atom-centered orbitals — •Andrea Sanfilippo¹, Xinguo Ren¹, Alexandre Tkatchenko¹, Patrick Rinke^1,2, Volker Blum¹, Karsten Reuter¹, and Matthias Scheffler¹ — ¹Fritz-Haber-Institut, Faradayweg 4-6, D-14195, Berlin (Germany) — ²University of California at Santa Barbara, CA 93106 (USA)

Well known deficiencies of present-day exchange-correlation functionals in density-functional theory (DFT) comprise the spurious self-interaction, the absence of non-local correlation (van der Waals, image interactions), and the absence of the derivative discontinuity with respect to changes in the electron number. We present a unified framework to overcome these deficiencies by many-body perturbation theory in the bare (Hartree-Fock, MP2) and the screened Coulomb interaction (Hedin’s GW approximation). Using numeric atomic-centered orbitals as basis sets, the efficiency of our formulation relies on the representation of intermediate quantities like the polarizability, and bare and screened Coulomb potentials by a second, auxiliary set of atom-centered basis functions. For an extended set of finite systems spanning individual atoms, small molecules (water dimer, methane, silane, benzene), metal clusters (Na_n), and biomolecules (alanine) we demonstrate that our implementation in the new DFT code FHI-aims [1] is significantly more efficient than existing formulations based on traditional plane wave or Gaussian basis sets.

[1] V. Blum et al., The FHI-aims project, www.fhi-berlin.mpg.de/aims/