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| ¡¡ Molecular Dynamics Simulation of Interaction
Between a 60¡ã Dislocation and Vacancy Defects in Si Crystal Abstract£ºTo investigate the dislocation motion characteristics in lowª²temperature£¨LT£©
buffer during the growing process of lattice mismatched heterostructure£¬a 60¡ã
dislocation dipole and 5 types of ringª²shaped hexagonal vacancy defects with their
different relative positions to the dislocation are modeled in a Si crystal via molecular
dynamics simulation£®Based on Parrinelloª²Rahman method£¬shear stress is exerted on the
model to move the dislocation£®The influences of different ringª²shaped hexagonal
vacancy defects on the 60¡ã dislocation movement are discussed£®It is found that all
kinds of ringª²shaped hexagonal vacancy defects may bend the dislocation line and delay
the dislocation movement£¬and during the course of intersection the dislocation line
sections relatively far away from the ringª²shaped hexagonal vacancy defect accelerate
first£¬and then decelerate£®The critical shear stress unpinning the 60¡ã dislocation
from the ringª²shaped hexagonal vacancy defect decreases as the temperature increases in
the models£¬and approaches a stable value of 0.6 GPa as the temperature is higher than
300 K£¬bellow the misfit stress in common SiGe heterostructures£¬ which indicates that
the 60¡ã dislocation can not be pinned by the ringª²shaped hexagonal vacancy defects in
this case£® |
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