Signature of surface periodicity in the electronic structure of Si(1 1 1)-(7 × 7)

The surface electronic structure of Si(1 1 1)- has been studied by angle-resolved photo electron spectroscopy. Replicas of the S 1 surface state are found in correspondence with several unit cells in the reciprocal space. This observation resolves in a direct way the long-standing dichotomy between the structural and electronic properties of the system previously discussed on the basis of the or R30° surface models.