Double domain solidC60on Si(111)7×7

We have grown fcc crystalline islands of ${\mathrm{C}}_{60}$ on a clean Si(111)7×7 surface. Scanning tunneling microscopy reveals that the islands are oriented primarily in two distinct directions independent of the island height and size. We show that this is a result of the pinning of ${\mathrm{C}}_{60}$ molecules at the corner holes associated with a disorder-to-order transition at the interface. Interlayer molecular interactions play a vital role in the process. The presence of two distinct island orientations is a manifestation of the formation of double domain solid ${\mathrm{C}}_{60}$ on the Si(111)7×7 surface.