Temperature Dependence of Photoemission Spectra and X-Ray Diffraction of Ag Nanofilm

Abstract

Temperature-dependent angle-resolved photoemission study for Ag nanofilm has been done in order to investigate in detail the quantized electronic structures. The angle-resolved photoemission spectra of Ag nanofilms exhibit the features derived from the quantized state of Ag sp valence electron as well as Shockley-type surface state. The linewidth of the quantized state broaden and its intensity decreases with increasing a temperature. The linear temperature dependence of linewidth is explained as the phonon contribution to the photohole lifetime width. From an analysis of temperature-dependent intensity based on the standard Debye theory, it is found that the “effective” Debye temperature of Ag nanofilm is much smaller than bulk values. This suggests that the standard Debye-Waller factor does not quantitatively explain the present temperature dependence. Connected with these results, we have carried out a temperature-dependent x-ray diffraction study in order to investigate the thermal lattice properties. From these results, we discuss the electron-phonon interaction in Ag nanofilm.