Order-disorder phase transition on the Pb-adsorbed Si(1Â 1Â 0) surface

A new reversible temperature-dependent phase transition on Pb/Si(1 1 0) was found by photoemission spectroscopy and low energy electron diffraction. The room temperature 1 × 1 surface was found to transit into low temperature 4 × 2 with a transition temperature of roughly 200 K. The phase transition does not induce a temperature-dependent variation in both the energy bands and the Si 2p and Pb 5d spectra. This indicates that the phase transition is close to an order-disorder one.