Signature of Surface Periodicity in the Electronic Structure of Si(1 1 1)-(7 × 7)

The surface electronic structure of Si(1 1 1)-[Formula: see text] has been studied by angle-resolved photo electron spectroscopy. Replicas of the S surface state are found in correspondence with several [Formula: see text] 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 [Formula: see text] or [Formula: see text] R30° surface models.