Physics of molecular deformation mechanism in 6H-SiC

Abstract

Even though there have been several studies in literature of 6H SiC, a
proper physics based understanding of the molecular deformation mechanisms of the
material under different loading conditions is still lacking. Experimentally, the brittle
nature of the material leads to difficulties associated with in-situ determination of
molecular deformation mechanisms of the material under an applied load; whereas,
the complex material structure along with the bonding environment prevents proper
computational identification of different types of inelasticity mechanisms within the
material. Molecular dynamics study (on successful verification of the interatomic
potential with experimental results) of pristine single crystals of 6H SiC have been
used to probe the physics of molecular deformation mechanisms of the material along
with its inherent orientational anisotropy. The study elucidates the experimentally
observed mechanisms of defect nucleation and evolution through a detailed analysis of
radial distribution functions, x-ray diffraction as well as phonon vibrational studies of
the single crystal. Studies have been presented at room temperature, initial high
temperature and different types of confinement effects of the material (including
hydrostatic and different biaxial loading cases). The confinement resulted in an
increase in stress and stiffness whereas increase in initial temperature resulted in a
decrease compared to uniaxial stress loading conditions at room temperature.