Nanoscale control of unbound and bound states of fullerene C60 molecules for ultradense data storage

The molecular-scale control of unbound and bound states of fullerene C₆₀ molecules has been investigated. We demonstrate that an ultrathin film of C₆₀ molecules and the use of a scanning tunneling microscope (STM) realize excellent controllability of reversible switching between the unbound and bound states of C₆₀ molecules at room temperature (RT). One of the two chemical states of C₆₀ molecules can be selectively realized by changing the polarity of the electric field between the STM tip and the C₆₀ film. This methodology for the chemical manipulation of unbound and bound states enables the writing, erasing, and rewriting of binary data in a C₆₀ film with a density of 190 Tbit/inch² at RT.