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

Abstract

In situ transmission electron microscopy observations of uniaxial compression of sub-300nm 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 {0001} planes at stresses above 7.8GPa. 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 〈11¯00〉. 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.