Electronic Band Structure Of Cuprous And Silver Halides: An All-Electron Gw Study

Group IB metal halides (CuX and AgX, X = Cl, Br, and I) are widely used in optoelectronic devices and photochemical catalysis due to their appropriate optical and electronic properties. First-principles calculations have confronted difficulties in accurately predicting their electronic band structures. Here, we study CuX and AgX with many-body perturbation theory in the GW approximation, implemented in the full-potential linearized augmented plane waves (FP-LAPW) framework. Comparing the quasiparticle band structures calculated with the default LAPW basis and the one extended by high-energy local orbitals (HLOs), denoted as LAPW+HLOs, we find that it is crucial to include HLOs to achieve sufficient numerical accuracy in GW calculations of these materials. Using LAPW+HLOs in semilocal density functional approximation based GW(0) calculations leads to good agreement between theory and experiment for both band gaps and the splitting between metal (Cu or Ag) d and X-p states. This work emphasizes the importance of numerical accuracy in the description of unoccupied states for quasiparticle band structure of materials with the d(10) electronic configuration.