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Related papers: Evolution of amorphous carbon across densities: an…

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We analyze the effects of sp^2/sp^3 bond-aspect ratio on the transport properties of amorphous carbon quasi-1D structures where structural disorder varies in a very non-linear manner with the effective bandgap. Using a tight-binding…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 Mikhail V. Katkov , Somnath Bhattacharyya

Hard spheres are ubiquitous in condensed matter: they have been used as models for liquids, crystals, colloidal systems, granular systems, and powders. Packings of hard spheres are of even wider interest, as they are related to important…

Disordered Systems and Neural Networks · Physics 2015-03-13 Giorgio Parisi , Francesco Zamponi

New carbon forms exhibiting extraordinary physico-chemical properties can be generated from nanostructured precursors under extreme pressure. Nevertheless, synthesis of such fascinating materials is often not well understood that results,…

We report on extended investigation of the thermal transport and acoustical properties on hard carbon samples obtained by pressurization of C60 fullerene. Structural investigations performed by different techniques on the same samples…

Disordered Systems and Neural Networks · Physics 2009-11-07 J. C. Lasjaunias , M. Saint-Paul , A. Bilusic , A. Smontara , S. Gradecak , A. M. Tonejc , A. Tonejc , N. Kitamura

A novel form of amorphous carbon with sp-sp2 hybridization has been recently produced by supersonic cluster beam deposition showing the presence in the film of both polyynic and cumulenic species [L. Ravagnan et al. Phys. Rev. Lett. 98,…

Transformation of amorphous carbon clusters into fullerenes under high temperature is studied using molecular dynamics simulations at microsecond times. Based on the analysis of both structure and energy of the system, it is found that…

Mesoscale and Nanoscale Physics · Physics 2017-08-07 Alexander S. Sinitsa , Irina V. Lebedeva , Andrey M. Popov , Andrey A. Knizhnik

Thermal conductivities $\Lambda $ of amorphous carbon thin films are measured in the temperatures range 80--400 K using the $3\omega $ method. Sample films range from soft a-C:H prepared by remote-plasma deposition ($\Lambda = 0.20$ W…

Materials Science · Physics 2009-10-31 Andrew J. Bullen , Keith E. O'Hara , David G. Cahill , Othon Monteiro , Achim von Keudell

Four sp3 carbon allotropes with six, eight, and 16 atoms per primitive cell have been derived using a combination of metadynamics simulations and topological scan. A chiral orthorhombic phase oC16 (C2221) was found to be harder than…

Materials Science · Physics 2012-06-26 Daniele Selli , Igor A. Baburin , Roman Martoňák , Stefano Leoni

We report a combined experimental and theoretical study of boron carbide under stress/deformation. A special rotating anvil press, the rotating tomography Paris Edinburgh cell (RotoPEC), has been used to apply torsional deformation to boron…

Crystalline $\rm Bi_2Se_3$ is one of the most explored three-dimensional topological insulator, with a $0.3\;\rm eV$ energy gap making it promising for applications. Its amorphous counterpart could bring to light new possibilities for large…

Materials Science · Physics 2021-12-14 Bruno Focassio , Gabriel R. Schleder , F. Crasto de Lima , Caio Lewenkopf , Adalberto Fazzio

We deform representative volume elements of amorphous carbon obtained from melt-quenches in molecular dynamics calculations using bond-order and machine learning interatomic potentials. A Drucker-Prager law with a zero-pressure flow stress…

We study the deposition of tetrahedral amorphous carbon (ta-C) films from molecular dynamics simulations based on a machine-learned interatomic potential trained from density-functional theory data. For the first time, the high $sp^3$…

Materials Science · Physics 2018-04-23 Miguel A. Caro , Volker L. Deringer , Jari Koskinen , Tomi Laurila , Gábor Csányi

Fracture is the ultimate source of failure of amorphous carbon (a-C) films, however it is challenging to measure fracture properties of a-C from nano-indentation tests and results of reported experiments are not consistent. Here, we use…

Materials Science · Physics 2021-02-17 S. Mostafa Khosrownejad , James R. Kermode , Lars Pastewka

We report a theoretical study of dielectric properties of models of amorphous Boron Nitride, using interatomic potentials generated by machine learning. We first perform first-principles simulations on small (about $100$ atoms in the…

The paper presents a cooperative consideration of Raman spectra of $^2$ amorphous carbons as well as the nature and type of their amorphicity. The latter was attributed to the amorphization of a new type named as enforced fragmentation. The…

Materials Science · Physics 2020-07-16 E. F. Sheka , Ye. A. Golubev , N. A. Popova

A quasi-2D semiconductor carbon allotrope called tetrahexcarbon, also named tetragraphene, was recently proposed featuring an unusual structure combining squared and hexagonal rings. Mechanical and electronic properties of tetragraphene…

Graphene, the one-atom-thick sp2 hybridized carbon crystal, displays unique electronic, structural and mechanical properties, which promise a large number of interesting applications in diverse high tech fields. Many of these applications…

Mesoscale and Nanoscale Physics · Physics 2016-09-27 Tommaso Cavallucci , Khatuna Kakhiani , Riccardo Farchioni , Valentina Tozzini

We present a new and efficient optimization method to determine the structure of disordered systems in agreement with available experimental data. Our approach permits the application of accurate electronic structure calculations within the…

Materials Science · Physics 2014-06-23 Jan H. Los , Thomas D. Kühne

In this note, we calculate the electronic properties of a realistic atomistic model of amorphous graphene. The model contains odd membered rings, particularly five and seven membered rings and no coordination defects. We show that…

Strongly Correlated Electrons · Physics 2009-12-04 V. Kapko , D. A. Drabold , M. F. Thorpe

Carbon fibres (CF) represent a significant volume fraction of modern structural airframes. Embedded into polymer matrices, they provide significant strength and stiffness gains over unit weight as compared to other competing structural…