Figure 1: Correlated switching in self-assembled molecular rotor crystals.
From: Correlated rotational switching in two-dimensional self-assembled molecular rotor arrays
(a) Surface-mediated Ullmann coupling reaction scheme. (b) STM image of a two-dimensional crystal composed of the reaction intermediate in which the ethyl rotors appear either as bright protrusions or depressions depending on their orientation. The reaction intermediates form an interlocked pattern and the ethyl rotors form active (exhibiting correlated switching; black arrows) and inactive rows (no switching; magenta arrows). Scale bar, 2 nm. (c) Zoom in of the active row with both colour-coded and molecular overlays. Yellow and blue circles indicate the up and down configurations of the ethyl rotors, respectively. An example of ethyl rotor indexing is shown where i+1 and i−1 denote the NN and FN of rotor i, respectively. Scale bar, 1 nm. (d) Same-pair (i, i+1) and long-range (i, i+3)-correlated switching observed when pulsing rotor i in the active row with the STM tip. The resultant current versus time traces are shown with the location of the STM tip pulses (±50 mV) marked with a red cross; scale bar, 0.5 nm, and imaging performed at −10 mV and 5 pA.
