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Electronic Surface and Interface States on Metallic Systems, E. Bertel and M. Donath, eds., (World Scientific, 1995), pp. 187-201.
Two- and three-dimensional aspects of surface state confinement
Cavendish Laboratory, Madingley Road, Cambridge, CB3 0HE, United Kingdom
Institute for Theoretical Physics, University of Nijmegen, Toernooiveld, NL-6525 ED Nijmegen, The Netherlands
Abstract
The confinement of surface state electrons on Cu(111) by nanoscale structures
is modelled in this paper by a cylindrical sheath potential on the surface.
The confined states can leak through the potential barrier and are also
scattered into bulk states, and the contributions of these processes to the
lifetime are discussed. Scattering into bulk states provides the most
important energy broadening mechanism in this calculation, but contrary to
experiment the broadening vanishes as the energy approaches the bottom of the
surface state band. The limitations of a two-dimensional treatment of the
scattering of surface states by surface potentials are discussed.
In a two-dimensional approximation, the sheath model potential can reproduce
very well the local density of states at the centre of a ring of discrete
s-wave scatterers.