Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 77: Focus Session: Frontiers of Electronic Structure Theory - Non-Equilibrium Phenomena at the Nano-Scale V (organized by O)

TT 77.4: Vortrag

Mittwoch, 2. April 2014, 17:00–17:15, TRE Ma

Studies of semiconducting pyrite and marcasite compounds using many-body perturbation theory in the GW approximation — •Timo Schena, Gustav Bihlmayer, Christoph Friedrich, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, Germany

FeS₂ pyrite and marcasite have recently gained renewed interest as materials for photovoltaic applications, due to their large optical absorption and abundance. Therefore, a reliable description of the fundamental band gap of these compounds within first-principles calculations is desirable. However, common density functional theory (DFT) often suffers from an underestimation of band gaps. This calls for beyond-DFT methods, e.g., the GW approximation, which is known to yield gaps in much better agreement with experiment. Although this is widely accepted for “simple” semiconductors, the situation is not well understood for more complicated cases, where the band edges differ in atomic and orbital character. In fact, we observe an uncommon band gap reduction in FeS₂ when applying single-shot GW on top of DFT, which might be problematic for photovoltaic applications [1]. In this work, we investigate the effects of the GW approximation on a couple of pyrite and marcasite compounds, employing the FLAPW code FLEUR and the GW code SPEX (www.flapw.de). In addition to single-shot GW, we also compare to the results of the recently implemented quasi-particle self-consistent GW approximation. We gratefully acknowledge funding from BMBF of the NADNuM project 03SF0402A.

[1] T. Schena et al. Physical Review B (accepted 2013)