Electrical conduction mechanism in ultrathin Pb (111) films formed on the $\text{Si}\left(111\right)\sqrt{3}\times \sqrt{3}\text{-Pb}$ surface has been investigated by means of in situ conductivity measurements, angle-resolved photoemission spectroscopy, and first-principles calculations. To investigate the origin of the bilayer oscillation observed in the present conductivity measurement, we perform some simulations based on the calculated band structure. They reveal that the density of states near the Fermi level cannot explain the bilayer oscillation, therefore, exclusively assigning it to the relaxation time. Surface roughness during the bilayer film growth seems to play a crucial role in the bilayer oscillation of the relaxation time.

• Received 20 June 2008

DOI:https://doi.org/10.1103/PhysRevB.78.245405