Dislocation glide-controlled room-temperature plasticity in 6H-SiC single crystals

Abstract

In situ transmission electron microscopy observations of uniaxial compression of sub-300 nm diameter, cylindrical, single-crystalline 6H-SiC pillars oriented along 〈0001〉 and at 45° with respect to 〈0001〉 reveal that plastic slip occurs at room-temperature on the basal {0 0 0 1} planes at stresses above 7.8 GPa. Using a combination of aberration-corrected electron microscopy, molecular dynamics simulations and density functional theory calculations, we attribute the observed phenomenon to basal slip on the shuffle set along 11̄00. By comparing the experimentally measured yield stresses with the calculated values required for dislocation nucleation, we suggest that room-temperature plastic deformation in 6H-SiC crystals is controlled by glide rather than nucleation of dislocations.