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arXiv · 1206.5379

Superhard sp3 carbon allotropes with odd and even ring topologies

Daniele Selli·Igor A. Baburin·Roman Martoňák·Stefano Leoni
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Abstract

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 monoclinic M-carbon and shows excellent stability in the high-pressure range. A second orthorhombic phase of Cmmm symmetry, by \sim 0.028 eV/atom energetically lower than W-carbon, can be formed from graphite at \sim 9 GPa. In general, the mechanical response under pressure was found to depend on the structure topology, which reflects the way rings are formed from an initial graphene layer stacking.

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Daniele Selli, Igor A. Baburin, Roman Martoňák, Stefano Leoni. 2012-06-23. Superhard sp3 carbon allotropes with odd and even ring topologies. https://doi.org/10.1103/physrevb.84.161411

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