Phonon contributions to photohole linewidths observed for surface states on copper

Abstract

We have observed the linear temperature dependence of the linewidth of surface states on Cu. These data allow the determination of a temperature coefficient for the phonon-hole coupling, which enters the linewidth as Γ=2π${\mathit{bk}}_{\mathit{BT}}$. For the s,p-like (Shockley) state at Γ¯ on Cu(111), we find b=0.137±0.015, in perfect agreement with earlier data of McDougall, Balasubramian, and Jensen [Phys. Rev. B 51, 13 891 (1995)]. The d-like (Tamm) state at M¯ on Cu(111) is characterized by a different b=0.085±0.015, which, however, agrees with the b=0.09±0.02 observed for a similar Tamm state on Cu(100). We suggest that the different spatial extent of the surface states is responsible for the different phonon-hole coupling. © 1996 The American Physical Society.