The surface excitation spectra of the Pd(110) surface is analyzed in the framework of the time-dependent density functional theory. The ab initio electronic structure of this surface is included into the evaluation of the surface response function using a linear response approach. At small momentum transfer the extrapolated energy of the surface plasmon is close to electron-energy-loss-spectroscopy measurements and can be understood considering the bulk Pd dielectric function. However, upon momentum increase the evaluated dispersion of the surface plasmon presents significant discrepancies with the published experimental data. While the experimental surface plasmon dispersion initially presents a strong negative slope, our calculations indicate a weak positive dispersion at all finite momentum transfers where this collective excitation is observed. Interestingly, we do not observe any noticeable effect on the collective surface excitations induced by the large number of surface states in the valence band of Pd(110). These states do not produce any additional mode at energies below the surface plasmon.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics