Energy-dependent cancellation of diffraction spots due to surface roughening

Puisto, S. R., Held, G. and King, D. A. (2005) Energy-dependent cancellation of diffraction spots due to surface roughening. Physical Review Letters, 95 (3). 036102. ISSN 1079-7114 doi: 10.1103/PhysRevLett.95.036102

Abstract/Summary

The low-energy electron diffraction (LEED) pattern of the step-kinked Pt{531} surface at 200 K shows energy-dependent cancellation of diffraction spots over unusually large energy ranges, up to 100 eV. This cannot be reproduced theoretically when a flat surface geometry is assumed. A relatively simple model of roughening, however, involving 0.25 ML of vacancies and adatoms leads to very good agreement with the experiment. The cancellation of intensities within a very narrow range of adatom or vacancy coverages is caused by the interference of electrons emerging from different heights but similar local environments. This is a rare example where the energy dependence of integrated LEED spot intensities is dramatically affected by the long-range arrangement of atoms.