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HL: Halbleiterphysik

HL 57: Theory of electronic structure

HL 57.4: Vortrag

Freitag, 31. März 2006, 11:45–12:00, BEY 118

All-electron GW approximation in the augmented-plane-wave basis-set limit — •Christoph Friedrich¹, Arno Schindlmayr¹, Stefan Blügel¹, and Takao Kotani² — ¹Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany — ²Department of Chemical and Materials Engineering, Arizona State University, Tempe, AZ 85287-6006, USA

The GW approximation for the electronic self-energy yields quasiparticle band structures in very good agreement with experiment, but almost all calculations so far are based on the pseudopotential approach. We have developed an implementation within the all-electron linearised augmented plane-wave (LAPW) method, which treats the core electrons explicitly. As errors resulting from the linearisation of the basis set are frequently overlooked, we here aim to investigate its influence on the GW self-energy correction. A systematic improvement is achieved by including additional local orbitals defined as second and higher energy derivatives of solutions to the radial scalar-relativistic Dirac equation, which constitute a natural extension of the LAPW basis set. Within this approach the linearisation error can be systematically reduced, and the exact augmented-plane-wave basis-set limit can be reached. While the electronic self-energy and the quasiparticle energies benefit from the better description of the unoccupied states, the resulting band gaps remain relatively unaffected.