Inverse lifetime of surface states on metals

We present the quasi-particle self-energy calculations of the inverse lifetimes (intrinsic linewidths) of Shockley surface states on Cu(111), Be(0001) and Mg(0001). The self-energy is evaluated within the GW approximation. The calculated linewidths are in very good agreement with recent high-resolution angle-resolved photoemission spectroscopy measurements. We demonstrate that a theory that directly incorporates an energy gap and a surface state localized within removes the existing large disagreement between the experimental results and previous theoretical predictions for Cu(111) and Be(0001). (C) 2000 Elsevier Science B.V. All rights reserved.