Journal article
Photoemission study of the surface state at Y on Cu(110): Band structure, electron dynamics, and surface optical properties
Publication Details
Authors:  Straube, P.; Pforte, F.; Michalke, T.; Berge, K.; Gerlach, A.; Goldmann, A.

Journal:  Physical Review B 
Journal acronym:  Phys. Rev.

Abstract
We report highresolution results from the wellknown "Shockley"type surface state localized around the (Y) over bar point of the Cu(110) surface Brillouin zone. Along <(Gamma Y)over bar> the effective mass is m*/m= 0.26+/0.03 and the bottom of the dispersion parabola at (Y) over bar shifts linearly with sample temperature T as E0 = (510+/15)meV +(0.26+/0.02 meV/K)T. We have also analyzed the photoemission linewidth Gamma(h) of this surface state. Our analysis results in an upper limit for the imaginary part of the selfenergy Im Sigma = Gamma(h)/2 less than or equal to( 16+/3)meV, which corresponds to a photohole lifetime tau greater than or equal to(2+/5)fs at (Y) over bar and T>0. On the basis of recent calculations of Gamma(h), for Cu(111) at <(Gamma)over bar> [Chulkov er al., Surf. Sci. (to be published)] we interpret Gamma(h) of Cu(110) at (Y) over bar by inelastic holeelectron interactions, with about 50% contribution each from surface band (inplane) and from threedimensional (coupling to substrate) decay channels. Finally we discuss the contribution of the (Y) over bar surface state to the surface optical properties as observed in both second harmonic generation and (onephoton) reflection anisotropy spectroscopy from Cu(110).