The Electron-Phonon Interaction at Vicinal Metal Surfaces Measured with Helium Atom Scattering

Recently, it was demonstrated that inelastic helium atom scattering from conducting surfaces provides a direct measurement of the surface electron-phonon coupling constant (mass enhancement factor lambda) via the temperature or the incident wave vector dependence of the Debye-Waller exponent. Here, previous published as well as unpublished helium atom scattering diffraction data from the vicinal surfaces of copper (Cu(11 alpha), with alpha = 3, 5, 7) and aluminum (Al(221) and Al(332)) were analyzed to determine lambda. The results suggested an enhancement with respect to the corresponding data for the low-index surfaces (111) and (001) above the roughening transition temperature. The specific role of steps compared to that of terraces is briefly discussed.