Photoemission studies of thin metallic overlayer sytems
Shapiro, Alan Paul
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/25219
Description
Title
Photoemission studies of thin metallic overlayer sytems
Author(s)
Shapiro, Alan Paul
Issue Date
1987
Doctoral Committee Chair(s)
Chiang, Tai-Chang
Department of Study
Physics
Discipline
Physics
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
photoemission studies
thin metallic overlayer systems
electronic structure
Language
en
Abstract
Angle-resolved photoemission spectroscopy was used to study Ag(lll) I
monolayers on six different substrates: Ni(OOl), Ni(lll), Cu(OOl),
Cu(lll), Au(lll), and Si(lll)-(7x7). The properties of surface states
were also examined for several related systems: Cu(lll) covered by
various thicknesses of Ag, and a bare Cu(332) stepped surface. Monolayer
overlayers that are incommensurate with the substrate [Ag on Ni(OOl),
Ni(lll), and Cu(lll)] or commensurate with the substrate only over a large
unit cell [Ag on Cu(OOl)] show electronic structures essentially
independent of the substrate orientation and material, except for an
overall shift in binding energy. The overlayer electronic structure is
somewhat different for the Ag/Au(lll) system, where there is a nearly
perfect overlayer-substrate lattice match as well as substantial overlap
in energy bands of like characters. In the Ag/Si system, partially
disordered overlayer growth and a strongly corrugated substrate surface
structure cause the overlayer features in the spectra to broaden
substantially. For thicker Ag overlayers on Cu(lll), the growth mode of
the Ag was determined to be layer by layer despite the large mismatch
between the two lattices. The Cu(lll} surface state was observed to
evolve monotonically for increasing Ag overlayer thickness to eventually
become the Ag(lll) surface state. The measured rate of shift of the
surface state binding energy can be explained qualitatively in terms of
the degree of localization of the surface-state wave functions. For the
stepped Cu(332) surface, a feature believed to be an L-gap surface state
is observed just below the Fermi edge in the photoemission spectra. The
properties this surface state are compared with known properties of the
Cu(lll) L-gap surface state.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
