Anomalous charge oscillations in the dynamical response of metals

Abstract

In recent calculations of optical response at a metal surface, an unusual set of oscillations have been found in the induced charge density. These oscillations only appear when a crystal potential is included in the calculation. They propagate deep into the bulk, but are incommensurate with the lattice. We illustrate the occurrence of such oscillations in simple systems, and discuss their origin. For more general cases, we find that the amplitude of the oscillations is sensitive to the amount of spatial variation in directions parallel to the surface of either the crystal potential or the probing field. We also discuss the challenge of detecting this phenomenon experimentally.

Absence of surface plasma waves on hard-wall surfaces

“…The chief purpose of the present work is to correct a historical mistake, that of the existence of SPWs on hard-wall surfaces. We show that the wave modes usually designated as SPWs in the infinite-barrier model 5,8,9,17,18,[21][22][23] (IBM)which idealizes a surface as a hard wall that constitutes a node of the electronic wave functions -are also empty of charges in the infinite wavelength limit though with frequency ω 0 . Hence, these modes are again of the same type as those found by Feibelman and they are not SPWs.…”