Fig. 1. STM and AFM images of FePc and the datively bonded CO-FePc complex.
a STM image of the FePc molecule with (indicated by the arrow) and without adsorption of CO, with the insert showing the chemical structure of FePc (set point: Vsample = +100 mV, I = 100 pA, scale bar: 3 nm). b, c Experimental AFM images of FePc with and without adsorbed CO, obtained using a CO-terminated tip (V = 0 V, A = 100 pm, scale bar: 0.5 nm) at tip heights z of +160 pm and -10 pm, respectively. The tip height z was set with respect to a reference height given by the STM set point (100 mV, 100 pA) above the bare Cu(111) substrate in the vicinity of the molecule. The minus sign of tip height z indicates a decrease of tip height. d, e Simulated AFM images corresponding to CO-FePc and FePc at tip heights of 554 pm and 300 pm. The tip height in the simulation is defined as the distance between the front atom of the tip and the average height of the FePc complex (excluding the decorated CO) (scale bar: 0.5 nm).