Indium √7x√3 on Si(111):: A nearly free electron metal in two dimensions -: art. no. 246404

We present measurements of the Fermi surface and underlying band structure of a single layer of indium on Si(111) with root7xroot3 periodicity. Electrons from both indium valence electrons and silicon dangling bonds contribute to a nearly free, two-dimensional metal on a pseudo-4-fold lattice, which is almost completely decoupled at the Fermi level from the underlying hexagonal silicon lattice. The mean free path inferred from our data is quite long, suggesting the system might be a suitable model for studying the ground state of two-dimensional metals.