PHONON CONTRIBUTIONS TO PHOTOHOLE LINEWIDTHS OBSERVED FOR SURFACE-STATES ON COPPER

We have observed the linear temperature dependence of the linewidth of surface states on Cu. These data allow the determination of a tempera ture coefficient for the phonon-hole coupling, which enters the linewi dth as Gamma=2 pi bk(B)T. For the s,p-like (Shockley) state at <(Gamma )over bar> on Cu(111), we find b=0.137+/-0.015, in perfect agreement w ith earlier data of McDougall, Balasubramian, and Jensen [Phys. Rev. B 51, 13 891 (1995)]. The d-like (Tamm) state at (M) over bar on Cu(111 ) is characterized by a different b=0.085+/-0.015, which, however, agr ees 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.