LEEM investigations of ion beam effects on clean metal surfaces: Quantitative studies of the driven steady state

The technique of low-energy electron microscopy (LEEM) pioneered by Bauer has been adapted here to the investigation of ion beam processes on crystal surfaces by the incorporation of an intense and tunable source of selectable, energetic ions into a LEEM designed by Tromp et al. In this paper we explain principles that constrain the design of this tandem instrument, to permit observation of surfaces during irradiation. We also describe experiments that probe the driven steady state of surfaces subject to the perturbation of a uniform and constant flux of self-ions. The emphasis is on the example of Pt^- ions irradiating the Pt(111) surface. We explore a regime of linear response at elevated temperature in which the driven nucleation and universal driven growth of surface islands, and the driven cycling of Bardeen-Herring sources and other surface clocks, may be understood in a fully quantitative manner.