Photoelectron-diffraction and photoelectron-holography study of a Ge(111) high-temperature surface phase transition
- Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822 (United States)
Further evidence for a reversible surface-disordering phase transition on Ge(111) occurring {similar to}150 K below the bulk melting point of 1210 K has been found using Ge 3{ital p} x-ray photoelectron diffraction (XPD). Azimuthal XPD data at takeoff angles of {theta}=19{degree} (including nearest-neighbor forward-scattering directions and yielding high surface sensitivity) and {theta}=55{degree} (for which second-nearest-neighbor scattering directions and more bulk sensitivity are involved) show abrupt decreases in intensity of {similar to}40% and {similar to}30%, respectively, over the interval of 900--1200 K. Photoelectron holograms and holographic images of near-neighbor atoms at temperatures above and below the phase transition indicate an identical near-neighbor structure for all atoms present in ordered sites. These combined diffraction and holography data indicate that by 1200 K the top 1--2 double layers of Ge atoms are completely disordered.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 7047841
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 45:20; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GERMANIUM
SURFACE PROPERTIES
CRYSTAL-PHASE TRANSFORMATIONS
HOLOGRAPHY
PHOTOELECTRON SPECTROSCOPY
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
ELECTRON SPECTROSCOPY
ELEMENTS
METALS
PHASE TRANSFORMATIONS
SPECTROSCOPY
TEMPERATURE RANGE
360602* - Other Materials- Structure & Phase Studies