Multi-phase superlattices and phase transitions in graphite intercalation compounds with Rb, Cs, K, Li

Recent electron diffraction and real space imaging experiments for alkali metal donor compounds are discussed and are shown to yield strong evidence for the coexistence of multiple phases for the in-plane intercalate structure. Island formation indicates the presence of coexisting multiphases. X-ray fluorescence and dark-field imaging measurements using the scanning transmission electron microscope indicate that the dark islands have a higher alkali metal concentration than the lighter background and that the superlattice diffraction pattern is associated with the islands.