Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 63: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles IV (jointly with TT)

O 63.7: Talk

Thursday, March 29, 2012, 12:15–12:30, HE 101

A periodic implementation of hybrid functionals for numeric atom-centered orbitals — Sergey Levchenko, Rainer Johanni, Xinguo Ren, Jürgen Wieferink, Patrick Rinke, •Volker Blum und Matthias Scheffler — Fritz-Haber-Institut der Max-Planck-Gesellschaft, D-14195 Berlin

Traditional density functional theory based on the electron density and its gradients has a successful track record in condensed matter theory, but is also subject to some well known limitations: For instance, the residual self-interaction of the electrons; or, failure to cover the fundamental band gap of solids. Hybrid density functionals that add some non-local exchange are becoming a de facto strategy to remedy such issues; however, evaluating the non-local exchange operator in periodic systems efficiently can be nontrivial. We here describe an implementation of periodic non-local exchange using numeric atom-centered basis functions within the FHI-aims [1] all-electron code. The implementation is based on a localized “resolution of identity” strategy for the Coulomb operator, coupled with efficient integral and density matrix screening operations (in real space) that allow to cover periodic systems up to (currently) O(100) atoms at essentially converged basis set accuracy, and seamlessly in parallel (memory and CPU time, tested up to hundreds of CPUs). We prove the accuracy of our approach for bulk semiconductors and their surfaces, using the PBE0 and HSE density functionals. [1] V. Blum et al., Comp. Phys. Comm. 180, 2175 (2009).