Understanding of the phase transformation from fullerite to amorphous carbon at the microscopic level.
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 approximately 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.
Moseler
M
M
Fraunhofer-Institut für Werkstoffmechanik IWM, Wöhlerstrasse 11, 79108 Freiburg, Germany.
Riedel
H
H
Gumbsch
P
P
Stäring
J
J
Mehlig
B
B