Dx. Shi et al., Direct observation of a local structural transition for molecular recording with scanning tunneling microscopy, APPL PHYS L, 77(20), 2000, pp. 3203-3205
We present a direct observation of a structural transition at molecular sca
le in an organic p-nitrobenzonitrile (PNBN) thin film using scanning tunnel
ing microscopy (STM). STM images clearly show an ordered molecular structur
e of unrecorded regions in the films, while the PNBN molecular arrangements
are disordered in the recorded regions. The current-voltage (I-V) measurem
ents from the STM demonstrate a great increase of the conductance transitio
n in the recorded regions after the voltage pulses. Those results suggest t
hat the recording mechanism may be due to a crystalline structural transiti
on, which is consistent with our previously proposed mechanism in another o
rganic system for ultrahigh density data storage. (C) 2000 American Institu
te of Physics. [S0003-6951(00)04746-X].