Dielectric functions and quasi-particle lifetimes in Ag: full-potential LMTO and LAPW GW approaches

Abstract

We report theoretical studies of dielectric functions and quasi-particle lifetimes in Ag by means of ab initio full-potential linear ‘muffin-tin’-orbitals LMTO GW and LAPW approaches. We show that the methods provide better description of the dielectric functions then the previous studies based on local density approximation of the density functional theory. In particular, the calculated electron energy loss function contains plasmon absorption peak which was absent in earlier calculations. The computed lifetimes of holes in the highest d-states are in good agreement with the experimental data. At lower energy large discrepancy between calculated and experimental data is observed which we refer to neglecting the vertex corrections.