Scanning tunneling microscopy of sulfide surfaces

Journal Article · Tue May 01 00:00:00 EDT 1990 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(90)90176-L· OSTI ID:6142116

Eggleston, C M; Hochella, Jr, M F ^[1]

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1. Stanford Univ., CA (USA)

A fundamental understanding of reactions that occur at mineral surfaces, many of which have bearing on important environmental issues, requires knowledge of atomic surface structures. Scanning tunneling microscopy (STM) is a new technique which can be used to image atomic surface structures in real space. We briefly review STM theory and interpret STM images of galena (PbS) and pyrite (FeS{sub 2}) surfaces by comparing the bias-voltage dependence of the images to the electronic structures of the materials. This approach amounts to a form of tunneling spectroscopy which may ultimately be used to identify individual atoms on mineral surfaces. STM imaging was accomplished on fresh fracture surfaces as well as on surfaces that had been exposed to air for long periods of time. For galena, the Pb and S sites are distinguishable, and the S sites appear to be imaged preferentially. A galena surface which had been oxidized in air for several months was imaged, suggesting either that oxidation products are very thin, occur in local patches on the surface, or are both non-conductive and not coherently bound to the galena surface. Iron appears to be imaged preferentially on fresh fracture surfaces of pyrite. Atomic positions on a pyrite growth surface were not those expected for a termination of the bulk pyrite structure; it is likely that a surface oxidation product was imaged.

• OSTI ID: 6142116
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 54:5; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GALENA
STRUCTURAL CHEMICAL ANALYSIS
SURFACE PROPERTIES
PYRITE
CHEMICAL REACTION KINETICS
GEOCHEMISTRY
MICROSCOPY
THERMODYNAMIC ACTIVITY
CHALCOGENIDES
CHEMISTRY
IRON COMPOUNDS
IRON SULFIDES
KINETICS
LEAD COMPOUNDS
LEAD SULFIDES
MINERALS
REACTION KINETICS
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
580000* - Geosciences