Diamondlike metastable carbon phases from shock-compressed C60 films

Abstract

Thin films of C60, 2.5-μm, have been shocked isentropically to 69 GPa, about 2200 K, and thermally quenched at rates up to 1011 K/s. The recovered specimen is transparent with a crystallographic habit, or ‘‘tilelike’’ structure, but it slowly transforms to a black highly disordered carbon at the ambient condition. The selected area electron diffraction patterns suggest that the transparent carbon phase contains an amorphous cubic diamond and n-diamond crystallites sized 50–350 Å in diameter.