EXPERIMENTAL AND THEORETICAL INVESTIGATION OF THE ELECTRONIC-STRUCTURE OF SILVER DEPOSITED ONTO INSB(110) AT 10-K

Ag films of thickness z with 0.5 less-than-or-equal-to z less-than-or-equal-to 60 monolayers (ML) evaporated onto a cleaved InSb(110) substrate at 10 K have been investigated through angle-resolved uv photoelectron spectroscopy (ARUPS) using synchrotron radiation and low-energy electron diffraction (LEED). The band structure has been calculated for bcc and fcc Ag. Inclusion of spin-orbit interaction makes the band structure near GAMMA very similar for bcc and fcc structures, whereas in the outer part of the Brillouin zone towards L and N distinct differences exist. From comparison between calculations and measurements we find some evidence that at 10 K and using an InSb(110) substrate bcc Ag is formed for thicknesses 2.5 less-than-or-equal-to z less-than-or-equal-to 30 ML. The LEED pattern also indicates that bcc Ag is formed with Ag(110) parallel-to InSb(110) as it was recently observed by Aristov et al. Annealing films with z > 5 ML to 300 K transforms these bcc films into fcc (111)-oriented Ag clusters. A 60-ML-thick annealed film exhibits as perfect ARUP spectra of the 4d bands as measured for a Ag(111) single-crystal surface, but exhibits no LEED pattern. For the thin bcc films a quantum-well state is observed.