Structure of amorphous carbon quenched from liquid in the pressure range 1-40 GPa: Molecular dynamic modeling

VS Dozhdikov and AY Basharin and PR Levashov, XXXII INTERNATIONAL CONFERENCE ON INTERACTION OF INTENSE ENERGY FLUXES WITH MATTER (ELBRUS 2017), 946, 012086 (2018).

DOI: 10.1088/1742-6596/946/1/012086

It is well known, that quenching from the liquid state is the basis of many methods for creating new materials with unique properties. Liquid and amorphous carbon are a mixture of atoms with different states of hybridization(sp(1), sp(2), sp(3)) owing to polymorphism. It is claimed that there is a tendency of growth of sp(1) atoms in liquid and amorphous carbon at decreasing pressure. Great interest has been shown recently to carbyne and pseudocarbynes, consisting of sp(1)-hybridizing atoms. These materials have unique optical and mechanical properties. In the present work a pressure dependence of the structure of amorphous carbon, quenched from liquid is studied by molecular dynamics simulation in the pressure range 1-40 GPa. The interaction between carbon atoms was determined by two bond-order potentials: Airebo and ReaxFF. These two potentials take into account the type of a chemical bond as well as breaking and formation of new chemical bonds during the modeling process. We study a bulk quenching from liquid carbon in the NPT ensemble at a constant pressure and determine the distribution of chemical bonds sp(1)-sp(2)-sp(3) in amorphous carbon during the quenching. Quenched liquid structure modeling at a pressure of 1 GPa and the structure of an amorphous carbon sample obtained experimentally at a pressure of 25 MPa by Raman spectroscopy showed that the sp(1) fraction of carbon was significant.

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