Figure 2
From: Electric-field-controlled phase transition in a 2D molecular layer
Self-assembly of CuPc molecules on the thallium-passivated Si(111) surface. (a) The Tl-passivated surface covered by almost 1 ML of CuPc molecules. Three domain orientations of the ordered CuPc array are shown. U s = −3 V. (b) STM image of the CuPc array superimposed by the structural model. U s = −2 V. Red, green and blue squares mark unit cells of the CuPc molecular arrays. (c) Top view of the relaxed structural model. Purple and gray spheres denote positions of Tl and Si atoms, respectively. (d,e) Isosurfaces of the constant difference of the charge density. The cross-section plane, the direction of the view and the volume imaged is marked in the panel c. The isovalues are set to 0.012 eÅ−3 (panel d) and 0.005 eÅ−3 (panel e). Red and blue colors represent electron density depletion and accumulation, respectively. (f,g) Side view of the relaxed structure superimposed by the plane-integrated charge transfer Δρ (panel f) and the cumulative charge transfer Q (panel g).
