Adsorption of tetrathiafulvalene (TTF) on Cu(1 0 0): can π-stacked 1-D aggregates be formed at low temperature?

We present a combined experimental and theoretical study that shows the formation of one-dimensional aggregates of tetrathiafulvalene (TTF) molecules along high symmetry directions of the Cu(1 0 0) metal surface at low temperatures. Our first principles calculations permit to explain the observations. We find an adsorption geometry of the molecules in a tilted configuration that is explained as the result of a delicate balance between intermolecular and molecule–surface attractive forces of comparable strength. The inclusion of van der Waals (vdW) forces in the description is instrumental to arrive at this conclusion.