Prediction of a superhard carbon-rich C-N compound comparable to diamond
Data(s) |
01/01/2015
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Resumo |
Until now, it has been a challenge both in experiment and in theory to design new superhard materials with high hardness values that are comparable to that of diamond. Here, by using first-principles calculations, we have introduced two new phases for a carbon-rich C-N compound with stoichiometry C3N, which is predicted to be energetically stable or metastable with respect to graphite and solid N2 at ambient pressure. It is found that C3N has a layered structure containing graphitic layers sandwiched with freely rotated N2 molecules. The layer-structured C3N is calculated to transform into a three-dimensional C2221 structure at 9 GPa with sp3-hybridized C atoms and sp2-hybridized N atoms. Phonon dispersion and elastic constant calculations reveal the dynamical and mechanical stability of the C2221 phase of C3N at ambient pressure. Significantly, first-principles ideal strength calculations indicate that the C2221 phase of C3N is a superhard material with an estimated Vickers hardness (∼76 GPa) comparable to that of diamond (60-120 GPa). The present results shed strong light on designing new superhard materials in the C-N system. |
Identificador | |
Idioma(s) |
eng |
Publicador |
American Chemical Society |
Relação |
DE150101617 DE140100716 http://dro.deakin.edu.au/eserv/DU:30081124/lei-predictionsuperhard-2015.pdf http://www.dx.doi.org/10.1021/acs.jpcc.5b10978 |
Direitos |
2015, American Chemical Society |
Tipo |
Journal Article |