Abstract
Preceding photoemission study on PbAu alloy reveals an anonymous parabolic energy band dispersing about the surface zone boundary M of Pb(111) at −2.1 eV. However, this band could not be observed in the direction 1 K M perpendicular to the mirror plane of photoemission measurement. This anonymous energy band could not be reproduced by the theoretical calculation of PbAu alloy, either. Therefore, we think this energy band should be related to a different phase than PbAu alloy. According to the previous theoretical study of Pb(111) surface electronic structures, we speculate that this special energy band is derived from the Pb(111) surface state induced by the adsorption of Au on the top. Therefore, in my research I design a series of systematic ways to prove this by comparing the intensities of photoemission spectra between the electronic structures of PbAu alloy phase and this special energy band at the low temperature 150 K and room temperature, respectively, in light of the fact that alloy phase in temperature dependent. Low energy electron diffraction was also used to specify the lattice structures of these two phases. We also deposited Bi on Pb films as a good comparison to the case of Au on Pb films.