Application of scanning tunneling microscopy to study adatom diffusion and lateral interactions: Sulfur on Re(0001) at low coverages

Journal Article · Thu Jul 01 00:00:00 EDT 1993 · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States)

DOI:https://doi.org/10.1116/1.578383· OSTI ID:6268316

Dunphy, J C ^[1]; Sautet, P ^[2]; Ogletree, D F; Salmeron, M B ^[3]

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1. Center for Advanced Materials, Material Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States) Department of Physics, University of California, Berkeley, Berkeley, California 94720 (United States)
2. Department of Physics, University of California, Berkeley, Berkeley, California 94720 (United States)
3. Center for Advanced Materials, Material Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)

Scanning tunneling microscopy (STM) imaging was applied to study coverages of less than 0.3 monolayers of sulfur on a rhenium(0001) surface. At coverages near one quarter monolayer sulfur forms a [ital p](2[times]2) ordered overlayer. Below this coverage islands of [ital p](2[times]2) ordered sulfur form, indicating an attractive interaction between sulfur atoms at twice the Re lattice spacing. Between these islands the STM images appear noisy. A correlation technique was applied to these images which showed that this noise was actually due to sulfur atoms diffusing on the same time scale as the STM image was acquired. The pair interaction energy between sulfur atoms at twice the Re lattice distance was determined by fitting the results of this correlation technique to an Ising model. The mobility of sulfur on the surface was further investigated by coadsorbing CO. This was found to compress the dilute sulfur overlayer into an ordered structure usually only seen at higher coverages. The transformation was observed by both low energy electron diffraction and STM. An upper limit for the energy required to compress the overlayer was extracted from the adsorption energy of CO. The energy barrier to diffusion was estimated from the average residence time of the diffusing sulfur atoms. These energies compare well with an extended Hueckel calculation.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6268316
• Journal Information: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States), Vol. 11:4; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON MONOXIDE
ADSORPTION
RHENIUM
ATOM TRANSPORT
SULFUR
DIFFUSION
ELECTRON DIFFRACTION
ISING MODEL
PAIRING ENERGY
SCANNING ELECTRON MICROSCOPY
ULTRAHIGH VACUUM
BINDING ENERGY
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
COHERENT SCATTERING
CRYSTAL MODELS
DIFFRACTION
ELECTRON MICROSCOPY
ELEMENTS
ENERGY
MATHEMATICAL MODELS
METALS
MICROSCOPY
NEUTRAL-PARTICLE TRANSPORT
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RADIATION TRANSPORT
SCATTERING
SORPTION
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties