Quantum interference patterns and electron confinement on a two-dimensional metal:: A scanning tunneling microscopy study -: art. no. 155407

We have investigated by scanning tunneling microscopy (STM) the electronic structure of a monolayer thick metallic film grown on top of a semiconducting substrate. In this system, which should behave as a true two-dimensional metal in the vicinity of the Fermi level, we have observed standing-wave patterns at low sample bias. The analysis of the modulations of the local density of states inside elongated resonators as a function of the bias shows that we probe a dispersive surface state with downward dispersion. The present STM results are in excellent agreement with previously reported photoemission data and with our band-structure ab initio calculations.