<i>Ab initio</i>simulations of amorphous carbon nitrides

Merchant, A. R.; McKenzie, David R.; McCulloch, D. G.

doi:10.1103/physrevb.65.024208

Cited by 29 publications

(20 citation statements)

References 30 publications

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“…For a -CN, there are some ab initio studies using the CPMD approach [ 16 , 17 ]. McKenzie and coworkers use random networks that were generated by the melt-and-quench method on a crystalline 64-atom supercell.…”

Section: Antecedents [ 1 ]mentioning

confidence: 99%

New Approaches to the Computer Simulation of Amorphous Alloys: A Review

et al. 2011

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In this work we review our new methods to computer generate amorphous atomic topologies of several binary alloys: SiH, SiN, CN; binary systems based on group IV elements like SiC; the GeSe2 chalcogenide; aluminum-based systems: AlN and AlSi, and the CuZr amorphous alloy. We use an ab initio approach based on density functionals and computationally thermally-randomized periodically-continued cells with at least 108 atoms. The computational thermal process to generate the amorphous alloys is the undermelt-quench approach, or one of its variants, that consists in linearly heating the samples to just below their melting (or liquidus) temperatures, and then linearly cooling them afterwards. These processes are carried out from initial crystalline conditions using short and long time steps. We find that a step four-times the default time step is adequate for most of the simulations. Radial distribution functions (partial and total) are calculated and compared whenever possible with experimental results, and the agreement is very good. For some materials we report studies of the effect of the topological disorder on their electronic and vibrational densities of states and on their optical properties.

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Section: Antecedents [ 1 ]mentioning

confidence: 99%

New Approaches to the Computer Simulation of Amorphous Alloys: A Review

et al. 2011

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“…However, at a very high N concentration disorder decreases sharply as if the sp 2 C structures stabilize. 22,27,28,[37][38][39][40] To resolve this complicated problem, we propose a model of correlated disorder (case (B)) where the distortion of carbon sp 2 structures is correlated with the distortion of incorporated nitrogen. The N doping centers experience some distortion due to interaction with the C atoms.…”

Section: Nitrogen Incorporated Carbon Structurementioning

confidence: 99%

“…[16][17][18] Many theoretical studies have attempted to explain the electronic structure and properties of nitrogen incorporated disordered carbon. [22][23][24][25][26][27][28][29] A model describing the distribution of the deeply localized states (e.g., nitrogen) in the graphitic carbon clusters can ideally explain the electronic transport properties of a À C films. We think that the previously discussed models of disorder should have been extended for explaining quantum transport in a carbon system which could show the features of resonant tunneling.…”

Section: Introductionmentioning

confidence: 99%

Enhanced tunnel transport in disordered carbon superlattice structures incorporated with nitrogen

Katkov

Bhattacharyya

2012

Journal of Applied Physics

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The possibility for enhanced tunnel transport through the incorporation of nitrogen in a quasi-one dimensional superlattice structure of amorphous carbon (a−C) made of sp2−C and sp3−C rich phases is shown by using a tight-binding model. The proposed superstructure can be described by a set of disordered graphite-like carbon clusters (acting as quantum wells) separated by a thin layer of diamond-like carbon (barriers) where the variation of the width and depth of the carbon clusters significantly control the electron transmission peaks. A large structural disorder in the pure carbon system, introduced through the variation of the bond length and associated deformation potential for respective carbon phases, was found to suppress the sharp features of the transmission coefficients. A small percentage of nitrogen addition to the carbon clusters can produce a distinct transmission peak at the low energy; however, it can be practically destroyed due to increase of the level of disorder of carbon sites. Whereas pronounced resonance peaks, both for C and N sites can be achieved through controlling the arrangement of the nitrogen sites of increased concentration within the disordered sp2−C clusters. The interplay of disorder associated with N and C sites illustrated the tunable nature of resistance of the structures as well as their characteristic times.

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“…At the first site, the nitrogen atom N1 is an uncharged 0 3 N site, where it forms three single σ bonds to neighboring sp 3 hybridized carbon atoms and a lone pair of electrons. This site is the most common nitrogen site [23] . The other nitrogen atom N2 is a 3 N + defect site, where it forms three σ and one π bonds to neighboring two sp 3 and one sp 2 hybridized carbon atoms and an unpaired electron.…”

Section: Structurementioning

confidence: 99%