Quasiparticle band-structure effects on the d hole lifetimes of copper within the GW approximation

We investigate the lifetime of d holes in copper within a first-principles GW approximation. At the G₀W₀ level the lifetime of the topmost d bands are in agreement with the experimental results and are four times smaller than those obtained in the ``on-shell'' calculations commonly used in literature. The theoretical lifetimes and band structure, however, worsen when further iterative steps of self-consistency are included in the calculation, pointing to a delicate interplay between self-consistency and the inclusion of vertex corrections. We show that the G<sub>0</sub>W<sub>0</sub> success in the lifetimes calculation is due to the opening of ``intraband'' decay channels that disappear at self-consistency.