Structure and phases of the Au(111) surface: X-ray-scattering measurements

Journal Article · Fri Feb 15 00:00:00 EST 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.4667· OSTI ID:5889732

Sandy, A R; Mochrie, S G.J. ^[1]; Zehner, D M ^[2]; Huang, K G; Gibbs, D ^[3]

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1. Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (USA)
2. Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6057 (USA)
3. Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (USA)

The results of a comprehensive synchrotron x-ray-scattering study of the clean, reconstructed Au(111) surface between 300 and 1250 K are presented. Two surface phases are identified and characterized. For {ital T}{lt}865 K, the reconstruction consists of a series of discommensurations, separating surface regions with the correct face-centered-cubic (fcc) {ital ABC} stacking sequence from regions with a faulted {ital ABA} stacking sequence. A key feature of this phase is the existence of an equilibrium density of kinks between rotationally equivalent domains. At 865 K, the reconstruction starts to lose long-range order. The first-order transformation to a disordered phase is complete by 880 K. In this phase, the topmost layer has hexagonal symmetry and is on the average isotropically compressed compared with bulk (111) planes. Between 880 and 1250 K the translational correlation length and the average compression of the overlayer evolve only slightly. Interpretation of the x-ray reflectivity, both specular and nonspecular, establishes, however, that the occupation of fcc {ital C} sites and faulted {ital A} sites is approximately constant throughout the temperature range studied. In addition, the separation between the top two layers is expanded 3% relative to the bulk (111) interlayer spacing and the surface-normal vibrational amplitude in the surface layers is enhanced with respect to the bulk value.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 5889732
• Journal Information: Physical Review, B: Condensed Matter; (USA), Vol. 43:6; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GOLD
SURFACE PROPERTIES
CRYSTAL FACES
HIGH TEMPERATURE
MEDIUM TEMPERATURE
ORDER-DISORDER TRANSFORMATIONS
SYNCHROTRON RADIATION
VERY HIGH TEMPERATURE
BREMSSTRAHLUNG
ELECTROMAGNETIC RADIATION
ELEMENTS
METALS
PHASE TRANSFORMATIONS
RADIATIONS
TRANSITION ELEMENTS
360102* - Metals & Alloys- Structure & Phase Studies