Low-energy positron diffraction from the (110) surfaces of GaAs and InP

Journal Article · Thu Jul 15 04:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.2400· OSTI ID:6345372

Chen, X M; Canter, K F ^[1]; Duke, C B; Paton, A ^[2]; Lessor, D L ^[3]; Ford, W K ^[4]

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1. The Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02254 (United States)
2. Xerox Webster Research Center, 800 Phillips Road, Webster, New York 14580 (United States)
3. Pacific Northwest Laboratory, K5-17 ISB-1, Richland, Washington 99352 (United States)
4. Advanced Materials Center and Department of Physics, Montana State University, Bozeman, Montana 59717 (United States)

The intensities of 16 nonequivalent beams of normally incident positrons diffracted from the (110) surfaces of GaAs and InP are reported. The sample temperature was approximately 110 K. The intensities were measured over the energy range 30 eV[le][ital E][le]200 eV. The atomic geometries of GaAs(110) and InP(110) were extracted from these intensities via their comparison with the predictions of a multiple-scattering model using the criterion of minimization of the x-ray [ital R] factor. The best-fit surface geometries resulting from these analyses are approximately bond-length-conserving top-layer and second-layer rotations characterized by the tilt angles ([omega][sub 1]=28.5[degree][plus minus]2.5[degree], [omega][sub 2]=[minus]3.5[degree][plus minus]3[degree]) for GaAs(110) and ([omega][sub 1]=24.5[degree][plus minus]1.5[degree], [omega][sub 2]=[minus]3.0[degree][plus minus]3[degree]) for InP(110). Comparable low-energy electron intensity data were obtained and analyzed for InP(110) leading to ([omega][sub 1]=31[sub [minus]5[degree]][sup [degree]+3[degree]] and [omega][sub 2]=[minus]3[degree][plus minus]3[degree]). Small changes ([Delta][ital d][le]0.07 A) in the bond lengths associated with the top-layer species are characteristic of the best-fit structures, but of these, only a small contraction ([Delta][ital d]/[ital d][le]3%) of the bond between the top-layer cation and second-layer anion seems likely to lie outside the uncertainties inherent in the analysis.

• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6345372
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:4; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
665100 -- Nuclear Techniques in Condensed Matter Physics -- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
ARSENIC COMPOUNDS
ARSENIDES
CHEMICAL BONDS
COHERENT SCATTERING
DIFFRACTION
ELEMENTARY PARTICLES
ENERGY RANGE
EV RANGE
FERMIONS
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
INDIUM COMPOUNDS
INDIUM PHOSPHIDES
LEPTONS
MATTER
MULTIPLE SCATTERING
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PNICTIDES
POSITRONS
SCATTERING
SURFACE PROPERTIES
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K