He diffraction study of the structural phase transition on the Ge(111) surface at 550 K

Journal Article · Fri Dec 15 04:00:00 EST 1989 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.457213· OSTI ID:5118013

Ha, J S; Greene, E F ^[1]

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1. Department of Chemistry, Brown University, Providence, Rhode Island 02912 (US)

A structural phase transition on the Ge(111) surface is investigated using thermal energy He scattering by observing the temperature dependence of several diffraction peaks. The presence of strong quarter-order peaks confirms that the Ge(111) surface has three orientational domains of a {ital c}(2{times}8) reconstruction at room temperature. As the temperature rises, all the superlattice peaks decrease in intensity without broadening and disappear above 550 K. In addition there is one striking feature which has not been observed in earlier low energy electron diffraction and reflection high energy electron diffraction experiments. The half-order peak shows continuous broadening and a shift of its maximum toward the specular peak as the temperature increases above 550 K. Consideration of several possible explanations for such a peak shift suggests that the transition, which may be driven by a charge density wave, is to an incommensurate phase.

• OSTI ID: 5118013
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 91:12; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

656003* -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMIC BEAM DIFFRACTION
ATOMIC BEAMS
BEAMS
COHERENT SCATTERING
CRYSTAL-PHASE TRANSFORMATIONS
DIFFRACTION
ELEMENTS
FLUIDS
GASES
GERMANIUM
HELIUM
HIGH TEMPERATURE
METALS
NONMETALS
PHASE TRANSFORMATIONS
RARE GASES
SCATTERING
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE