https://doi.org/10.1007/s10051-001-8689-y
Metastable structures of Dy layers adsorbed on Mo(112) and their transformations
1
Institute of Physics, Natl. Academy of Sciences of Ukraine,
Prospect Nauki 46, UA-03039, Kyiv-39, Ukraine
2
Institut für Festkörperphysik, Universität Hannover,
Appelstrasse 2, 30167 Hannover, Germany
Corresponding author: a pfnuer@fkp.uni-hannover.de
Received:
15
June
2001
Published online: 15 December 2001
Ordering of dysprosium on Mo(112) up to 1.5 monolayers has
been investigated by LEED and work function
analysis after adsorption at 100 K and annealing between 200 and
1000 K. At low annealing
temperatures (< 350-600 K)
ordered structures are found, which are changed or even destroyed irreversibly
by annealing steps to higher temperatures.
At coverages, θ, up to 0.3 monolayer
a not strictly
commensurate chain structure is seen, which coexists up to
with a one-dimensionally incommensurate c(
) structure. At higher
coverages up to the physical monolayer at
,
incommensurate (
) followed by oblique (
) structures
are seen with n continuously variable with coverage. The second layer forms a
p
structure. Annealing to higher temperatures causes
irreversible structural transitions with strongly coverage dependent
properties. Up to
, only a glass-like disordered phase is
formed,
which cannot be ordered again. In contrast, the rectangular incommensurate
structures between
remain unchanged upon annealing,
whereas the structures at higher coverages and those of the second layer are
transformed into commensurate
structures with integer s.
Geometrical models are presented for the non-annealed structures and possible
origins for the two-dimensional concentration dependent vitrification of the
Dy layers are discussed.
PACS: 68.55.-a – Thin film structure and morphology / 64.70.Pf – Glass transitions / 61.14.Hg – Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001