2 research outputs found
Atomistic modeling of amorphous silicon carbide: An approximate first-principles study in constrained solution space
Localized basis ab initio molecular dynamics simulation within the density
functional framework has been used to generate realistic configurations of
amorphous silicon carbide (a-SiC). Our approach consists of constructing a set
of smart initial configurations that conform essential geometrical and
structural aspects of the materials obtained from experimental data, which is
subsequently driven via first-principles force-field to obtain the best
solution in a reduced solution space. A combination of a priori information
(primarily structural and topological) along with the ab-initio optimization of
the total energy makes it possible to model large system size (1000 atoms)
without compromising the quantum mechanical accuracy of the force-field to
describe the complex bonding chemistry of Si and C. The structural, electronic
and the vibrational properties of the models have been studied and compared to
existing theoretical models and available data from experiments. We demonstrate
that the approach is capable of producing large, realistic configurations of
a-SiC from first-principles simulation that display excellent structural and
electronic properties of a-SiC. Our study reveals the presence of predominant
short-range order in the material originating from heteronuclear Si-C bonds
with coordination defect concentration as small as 5% and the chemical disorder
parameter of about 8%.Comment: 16 pages, 7 figure