Phonon-Induced Surface Charge Density Oscillations in Quantum Wells: A First-Principles Study of the (2 x 2)-K Overlayer on Be(0001)
Abbreviated Journal Title
J. Phys. Chem. A
ALKALI-METAL ADSORPTION; HELIUM-ATOM SCATTERING; AB-INITIO; HE-SCATTERING; NOBLE-METALS; SUPERCONDUCTIVITY; CU(111); GRAPHITE; MONOLAYER; EXPANSION; Chemistry, Physical; Physics, Atomic, Molecular & Chemical
Density functional perturbation theory has been applied to study the surface vibrations of (2 x 2)-K monolayer on the Be(0001) surface. We present the full phonon dispersion curves along the high symmetry directions of the surface Brillouin zone (SBZ) together with the layer-projected phonon density of states and the phonon-induced surface charge density oscillations at (Gamma) over bar and (M) over bar for the alkali SV and L modes. Surprisingly, at the (M) over bar point, the L-phonon displacements produce a more pronounced perturbation on the surface charge density than the SV-phonon displacements. These results apparently solve the long-standing question regarding helium atom scattering (HAS) experiments performed on the similar system (2 x 2)-K on graphite, where the alkali SV phonon mode is not observed. Moreover, this result confirms the previous finding that HAS from free-electron metal surfaces probes directly the phonon-induced charge density oscillations and the related electron-phonon interaction.
Journal of Physical Chemistry A
"Phonon-Induced Surface Charge Density Oscillations in Quantum Wells: A First-Principles Study of the (2 x 2)-K Overlayer on Be(0001)" (2011). Faculty Bibliography 2010s. 1176.