Structural change in graphite under electron irradiation at low temperatures

Abstract Changes in crystallographic and electronic structure of electron-irradiated graphite were examined at low temperatures by means of transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS). The long range order within the basal planes at the low temperatures was lost more quickly than at room temperature, which hardly affected the continuous changes in electronic and short range structures. This was mainly caused by the faster fragmentation of the crystal into pieces with the local structure maintained. The basal plane buckling and lattice dilation in the c -direction, similar to the previous results obtained at room temperature, suggest the local formation of non-hexagonal atomic rings, on the analogy of fullerenes, by the displacement damage incorporated with electronic excitations.