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Understanding of the phase transformation from fullerite to amorphous carbon at the microscopic level

: Moseler, M.; Riedel, H.; Gumbsch, P.; Stäring, J.; Mehlig, B.


Physical review letters 94 (2005), Nr.16, Art. 165503
ISSN: 0031-9007
ISSN: 1079-7114
Fraunhofer IWM ()
fullerene and fullerene-related material; mechanical property of nanoscale material; structural transition in nanoscale material; microscopic level; amorphous carbon

We study the shock-induced phase transformation from fullerite to a dense amorphous carbon phase by tight-binding molecular dynamics. For increasing hydrostatic pressures P, the C60 cages are found to polymerize at P<10 GPa, to break at P about 40 GPa, and to slowly collapse further at P>40 GPa. By contrast, in the presence of additional shear stresses, the cages are destroyed at much lower pressures (P<30 GPa). We explain this fact in terms of a continuum model, the snap-through instability of a spherical shell. Surprisingly, the relaxed high-density structures display no intermediate-range order.