Evolution of amorphous carbon across densities: An inferential study. (May 2018)

• Record Type: Journal Article
• Authors: Bhattarai, Bishal; Pandey, Anup; Drabold, D.A.
• Is Part Of: Carbon. Volume 131(2018)
• Page Start: 168
• Page End: 174
• Publication Date: 2018-05
• Subjects: ab initio -- Reverse monte carlo -- Inverse modeling -- Amorphous carbon -- Phonons; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2018.01.103
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: In this paper, we offer large and realistic models of amorphous carbon spanning densities from 0.95 g / c m 3 to 3.5 g / c m 3 . The models are designed to agree as closely as possible with experimental diffraction data while simultaneously attaining a local energy minimum of a density functional Hamiltonian. The structure varies dramatically from interconnected wrapped and defective s p 2 sheets at 0.95 g / c m 3 to a nearly perfect tetrahedral topology at 3.5 g / c m 3 . Force Enhanced Atomic Refinement (FEAR) was used and is shown here to be advantageous relative to conventional ab initio melt quench methods. We thoroughly characterize our models by computing structural, electronic and vibrational properties. The vibrational density of states of the 0.95 g / c m 3 model is strikingly similar to monolayer amorphous graphene. Our s p 2 / s p 3 ratios are close to experimental predictions where available. Graphical abstract: Image 1