Surface wake in the random-phase approximation

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.13399· OSTI ID:6129586

Garcia de Abajo, F J ^[1]; Echenique, P M ^[2]

---

1. Departamento de Ciencias de la Computacion e Inteligencia Artificial, Facultad de Informatica, Universidad del Pais Vasco, Apartado 649, 20080 San Sebastian (Spain)
2. Departamento de Fisica de Materiales, Facultad de Quimica, Universidad del Pais Vasco, Apartado 1072, 20080 San Sebastian (Spain)

The scalar-electric-potential distribution set up by an ion traveling in the vicinity of a plane solid-vacuum interface, that is, the surface-wake potential, is investigated with the specular-reflection model to describe the response of the surface and with the random-phase approximation for the dielectric function of the bulk material. This permits us to address the study of the low-velocity surface wake: the static potential is found to have a dip at the position of the ion; that dip is shifted towards the direction opposite to the velocity vector for velocities smaller than the threshold of creation of plasmons ([approx]1.3[ital v][sub [ital F]]). Extensive numerical calculations are presented for an ion both inside and outside aluminum. Comparison to the results obtained with the plasmon-pole dielectric function indicates excellent agreement for velocities larger than [approx]1.3[ital v][sub [ital F]]. On the other side, the possibility of surface-wake riding is suggested, by analogy with bulk-wake riding postulated in the past. In it, the electron would be bound in the first trough of the surface-wake potential set up when the ion describes a grazing trajectory. The main feature introduced by the surface with respect to the bulk consists of allowing the use of ions of higher charge, reducing in this way the relative importance of the electron self-energy, and in addition, giving rise to larger binding energies. When the ion beam is directed along a special direction of an oriented crystal surface, the mechanism of resonant coherent excitation could provide a way for experimentally detecting this phenomenon through the emission of the bound electron with well-defined energy and around a preferential direction.

• OSTI ID: 6129586
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:18; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

665200 -- Solid-State Plasma-- (1992-)
665300* -- Interactions Between Beams & Condensed Matter-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COUPLING
DIELECTRIC PROPERTIES
ELECTRIC POTENTIAL
ELECTRICAL PROPERTIES
ELECTRON-ION COUPLING
INCIDENCE ANGLE
NUMERICAL SOLUTION
PHYSICAL PROPERTIES
PLASMONS
QUASI PARTICLES
RANDOM PHASE APPROXIMATION
SURFACES