Quasiparticle self-consistent GW analysis in iron-based superconductors

Since the early theoretical study of iron-based superconductors, the density functional theory (DFT) has given great contributions to understand material properties, e.g. magnetic/orbital structure, pairing mechanism of superconductivity, etc. However, the LDA/GGA exchange-correlation potential in conventional DFT calculations is insufficient to describe the electronic state observed experimentally, such as in the angular resolved photoemission spectroscopy (ARPES) and de Hass van Alphen (dHvA) measurement [1-3]. In this study, we calculated the electronic band structure of iron-based superconductors with the quasiparticle self-consistent GW (QSGW) method. We found that the QSGW can improve the LDA/GGA band structure and Fermi surface in most cases. We will summarize the result and discuss the superconducting gap in the obtained QSGW band structure. [1] A. A. Kordyuk et al., Phys. Rev. B 83 134513 (2011). [2] K. Okazaki et al., Science 337 1314 (2012). [3] T. Terashima et al., J. Phys. Soc. Jpn. 79 053702 (2010).