TEMPERATURE-DEPENDENCE OF SHOCKLEY-TYPE SURFACE-ENERGY BANDS ON CU(111), AG(111) AND AU(111)

Using angle-resolved photoemission at very high resolution we have mea sured thermally induced energy shifts of the Shockley surface states o bserved around the center <(Gamma)over bar> of the surface Brillouin z ones on the noble metal (111) surfaces. Based on calculations using th e one-dimensional multiple reflection model we demonstrate that the ob served shifts can be quantitatively traced back to the temperature-dep endent shift of the relevant bulk band gaps which support these surfac e states. We have addressed care to a precise investigation of the <(G amma)over bar> state on Ag(111), since conflicting results had been re ported earlier. Its initial state energy at <(Gamma)over bar> is given by E(0)(T)= -(75 +/- 5) meV + (0.17 meV/K) T in the temperature range up to about 600 K.