The growth of Iron phthalocyanine (FePc) on InSb(001)c(8x2) at sub-monolayer coverage has been investigated with Scanning Tunneling Microscopy (STM). FePc adsorbs flat, centered on the in rows both at 70K and at room temperature (RT). However, the shapes of the two-dimensional molecular islands are fundamentally different; while the RT-growth results in chain-like structures along the [110]direction, as already observed for other Pc's adsorbed on the same surface, the islands are prolonged along the [-110], i.e. perpendicular to the substrate rows at 70K.
The observations are explained based on a recently observed new surface phase at low temperature, resulting in structural domains on the surface. The molecular growth front follows the propagatingdomain boundary that freezes at low temperature.