Bulk-like Si(001) atomic rearrangement artificially created at the Ge/Sb/Si(001) interface

We report here on the electronic properties of the Ge/Sb/Si(001) interface formation studied by very high-energy-resolution photoemission spectroscopy using synchrotson radiation. Surface- and bulk-sensitive measurements of the core levels of the different atomic species give a clear indication of the occurrence of a site exchange process between germanium and antimony, when Ge is deposited on the already prepared Sb/Si(001) interface. We demonstrate that the use of surfactant atoms like Sb at the strained Ge/Si(001) interface produces a perfect epitaxial interface, where the Si atoms are in register with the bulk geometrical positions.