TY - JOUR

T1 - Metastable structures of Dy layers adsorbed on Mo(112) and their transformations

AU - Fedorus, A.

AU - Koval, V.

AU - Naumovets, A.

AU - Pfnür, Herbert

PY - 2001/12

Y1 - 2001/12

N2 - 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 (6 × 1) not strictly commensurate chain structure is seen, which coexists up to θ = 0.58 with a one-dimensionally incommensurate c(1.56 × 2) structure. At higher coverages up to the physical monolayer at θ ≈ 0.77, incommensurate (n × 2) followed by oblique (n × 1) structures are seen with n continuously variable with coverage. The second layer forms a p(1.33 × 1) structure. Annealing to higher temperatures causes irreversible structural transitions with strongly coverage dependent properties. Up to θ = 0.58, only a glass-like disordered phase is formed, which cannot be ordered again. In contrast, the rectangular incommensurate structures between 0.58 < θ < 0.68 remain unchanged upon annealing, whereas the structures at higher coverages and those of the second layer are transformed into commensurate (s × 1) 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.

AB - 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 (6 × 1) not strictly commensurate chain structure is seen, which coexists up to θ = 0.58 with a one-dimensionally incommensurate c(1.56 × 2) structure. At higher coverages up to the physical monolayer at θ ≈ 0.77, incommensurate (n × 2) followed by oblique (n × 1) structures are seen with n continuously variable with coverage. The second layer forms a p(1.33 × 1) structure. Annealing to higher temperatures causes irreversible structural transitions with strongly coverage dependent properties. Up to θ = 0.58, only a glass-like disordered phase is formed, which cannot be ordered again. In contrast, the rectangular incommensurate structures between 0.58 < θ < 0.68 remain unchanged upon annealing, whereas the structures at higher coverages and those of the second layer are transformed into commensurate (s × 1) 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.

KW - 61.14.Hg Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)

KW - 64.70.Pf Glass transitions

KW - 68.55.-a Thin film structure and morphology

UR - http://www.scopus.com/inward/record.url?scp=0011843081&partnerID=8YFLogxK

U2 - 10.1007/s10051-001-8689-y

DO - 10.1007/s10051-001-8689-y

M3 - Article

AN - SCOPUS:0011843081

VL - 24

SP - 395

EP - 403

JO - European Physical Journal B

JF - European Physical Journal B

SN - 1434-6028

IS - 3

ER -