CONCENTRATION-DEPENDENT EFFECTIVE MASSES OF TAMM-STATES AT THE CU(100) AU SURFACE ALLOY/

We report a high-resolution photoemission study of the d-like surface state residing on the Cu(1 0 0)/Au surface alloy around the (M) over b ar-point of the Cu(1 0 0) surface Brillouin zone. When going from clea n Cu(1 0 0) to the fully developed Cu(1 0 0)c(2 x 2)Au outermost layer , the inverse effective mass characterizing the surface band dispersio n with k(parallel to) increases by about 2.0, almost linearly with Au concentration between zero and 50%. We discuss an interpretation in te rms of additional electronic charge density in the surface plane. (C) 1997 Elsevier Science Ltd.