Atomic-resolution study of lattice distortions of buried In{sub x}Ga{sub 1{minus}x}As monolayers in GaAs(001)
- Department of Materials Science and Engineering and Materials Research Center, Northwestern University, Evanston, Illinois 60208 (United States)
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
X-ray standing wave measurements were used to study the strain in one monolayer of pseudobinary alloy In{sub x}Ga{sub 1{minus}x}As buried in GaAs(001) by molecular-beam epitaxy. The measured In position along the [001] direction exhibited a nearly linear dependence on the In concentration {ital x}, thus supporting the validity of macroscopic continuum elasticity theory at the one-monolayer limit. A random-cluster calculation using a valence force field was performed to explain microscopically the origin of the vertical expansion of the strained monolayer observed by the experiment. The calculated As-In-As bond angle and the positions of the first-nearest-neighbor As atoms of In suggest that the nearly linear dependence of the In height on the alloy composition is a combined result of the As-In-As bond bending and the local lattice distortion at the GaAs/In{sub x}Ga{sub 1{minus}x}As interface. The calculated In-As and Ga-As bond lengths were found to depend weakly on the In concentration, consistent with an earlier calculation for the case of a thick In{sub x}Ga{sub 1{minus}x}As film on GaAs(001) and the available x-ray absorption fine-structure data. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 690746
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 60, Issue 19; Other Information: PBD: Nov 1999
- Country of Publication:
- United States
- Language:
- English
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