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SYME: Symposium Frontiers of Electronic Structure Theory: Many-body Effects on the Nano-Scale

SYME 7: Frontiers of Electronic Structure Theory: Many-Body Effects on the Nano-Scale VI

SYME 7.8: Talk

Thursday, March 19, 2015, 17:00–17:15, MA 004

Improved Ground State Electronic Structure and Optical Dielectric Constants With a Semi-Local Exchange Functional — •Vojtěch Vlček¹, Gerd Steinle-Neumann¹, Linn Leppert¹, Rickard Armiento², and Stephan Kümmel¹ — ¹University of Bayreuth, Germany — ²Linköping University, Sweden

For a set of solids, we explore a recently developed generalized gradient exchange functional (AK13) that has two characteristic features: its enhancement factor diverges for large reduced density gradients s as sln(s) and its potential changes discontinuously at integer electron numbers. We apply the functional to semiconductors, Mott insulators, and ionic crystals and compare results for band structure and dielectric constants with a standard GGA. The AK13 functional provides a better description of the KS orbitals and we observe a qualitative improvement both in the bandgaps and in the optical dielectric constants, especially for the small gap semiconductors we explore (Ge, α-Sn, and CdO)