"Debye-Scherrer Ellipses" from 3D Fullerene Polymers: An Anisotropic Pressure Memory Signature

High-pressure studies on fullerenes have previously shown the existence of one- and two-dimensional (2D) polymerized C$_{60}$ structures. Synchrotron radiation measurements, performed on C$_{60}$ samples quenched from 13 gigapascals and 820 kelvin, yield unambiguous proof for the existence of a three-dimensional (3D) polymerized C$_{60}$ derivative. Moreover, unusual ellipsoidal Debye-Scherrer diffraction patterns are observed, which shows that the giant anisotropic deformation induced by the nonhydrostatic compression is retained in the quenched samples. The multiple bonding possibilities of the highly symmetrical C$_{60}$ allow the retention (down to ambient pressure) of the deformation, a phenomenon reported previously only under high pressure.