Figure 1
From: Electric-field-controlled phase transition in a 2D molecular layer
Field-induced switching of the CuPc self-assembled molecular array. (a) Change of a domain orientation (1) and position (2) as a response to voltage pulses. Purple stars mark positions above which the pulses were applied. The image was taken at the sample bias U s = −2.3 V. The inset depicts the structural model of a CuPc molecule. Red and green dots mark positions of molecules in the molecular structures with different orientations. (b) STM image of the CuPc molecular array taken at the sample bias of −1.7 V, which is close to the threshold of imaging the stable arrays. Red arrows indicate the scanning direction. Green bars denote the length of 3 nm. (c,e) Shape of the triangular voltage pulse and corresponding dependence of the domain change probability on the peak voltage of the pulse U F . The values of probability were acquired from the 320 voltage pulses applied over the same domain. (d,f) Shape of the rectangular voltage pulse and corresponding dependence of the domain change probability on the pulse duration. The results were acquired from 100 voltage pulses applied over the same domain. Dashed line denotes ideal probability of random switching in a system of 45 domains (see Supplementary). The error bars represent a range of two standard deviations. Note that absolute values of the voltages and probabilities can vary for different STM tips and different surface coverages, but the character of the measured probability dependence remains the same.
