Stepped metal surfaces are natural systems for studying lateral quantum confinement [1]. Au(788) is a surface vicinal to the (111) plane that reconstructs and forms stable 3.8 nm wide periodic monatomic steps with (111) orientation. Step edges terminate in {111} microfacets. Electron wave functions are confined laterally in a direction perpendicular to the steps and contribute a 1D-like quantum well state to the Au(111) electronic structure. To probe this structure-property relationship we scatter hyperthermal energy alkali ions from the surface and measure the energy and neutral fraction of the scattered ions. By analyzing our data with the classical trajectory simulation SAFARI, ions scattered from the steps can be clearly distinguished from the step edge scattering events. The neutral fraction of scattered alkali ions is sensitive to the electrostatic potential directly above a scattering site and can detect quantum confined states [2]. Measured neutral fractions for different species of alkali ions are interpreted with a model of multi-state resonant charge transfer.

[1] A. Mugarza, A. Mascaraque, V. Perez-Dieste, V. Repain, S. Rousset, F. J. Garcia de Abajo and J. E. Ortega. Phys. Rev. Lett. 87, 107601 (2001).

[2] G. F. Liu, Z. Sroubek and J. A. Yarmoff. Phys. Rev. Lett. 92, 216801 (2004).