Maximally-localized Wannier functions for GW quasiparticles

Recent efforts carrying the GW many-body approximation to self-consistency have given improved electronic-structure results.$^{1}$ However, one is left with self-energy operators only on the grid of \textbf{k} points used for Brillouin-zone integration, unlike the case of DFT where the local self-consistent potential allows calculation of the band structure on arbitrary \textbf{k} points (e.g., along symmetry lines). As maximally-localized Wannier functions$^{2}$ (MLWF) provide a basis for a highly accurate approach to band interpolation, we have combined the \textsc{wannier90} code for MLWF with the self-consistent GW capabilities of the \textsc{abinit} code to efficiently extend the GW grid calculation to a full band structure. MLWF also provide an intuitive picture of the orbital character and bonding of groups of bands, as well as a quantitatively accurate measure of electric polarization.$^{2}$ Differences between quasiparticle$^{3}$ MLWF and their LDA counterparts examined to date (Si and perovskite SrZrS$_{3}$) have proven small, but the visualization of significant many-body effects through MLWF remains an intriguing possibility. 1. F. Bruneval \textit{et al}., Phys. Rev. B \textbf{74}, 045102 (2006). 2. N. Marzari and D. Vanderbilt, Phys. Rev. B \textbf{56}, 12 847 (1997). 3. M. van Schilfgaarde \textit{et al}., Phys. Rev. Lett. \textbf{96}, 226402 (2006).