Atomistic modeling of amorphous silicon carbide: An approximate first-principles study in constrained solution space - Condensed Matter > Disordered Systems and Neural NetworksReportar como inadecuado




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Abstract: Localized basis ab initio molecular dynamics simulation within the densityfunctional framework has been used to generate realistic configurations ofamorphous silicon carbide a-SiC. Our approach consists of constructing a setof smart initial configurations that conform essential geometrical andstructural aspects of the materials obtained from experimental data, which issubsequently driven via first-principles force-field to obtain the bestsolution in a reduced solution space. A combination of a priori informationprimarily structural and topological along with the ab-initio optimization ofthe total energy makes it possible to model large system size 1000 atomswithout compromising the quantum mechanical accuracy of the force-field todescribe the complex bonding chemistry of Si and C. The structural, electronicand the vibrational properties of the models have been studied and compared toexisting theoretical models and available data from experiments. We demonstratethat the approach is capable of producing large, realistic configurations ofa-SiC from first-principles simulation that display excellent structural andelectronic properties of a-SiC. Our study reveals the presence of predominantshort-range order in the material originating from heteronuclear Si-C bondswith coordination defect concentration as small as 5% and the chemical disorderparameter of about 8%.



Autor: Raymond Atta-Fynn, Parthapratim Biswas

Fuente: https://arxiv.org/







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