Theory of ion-stimulated electron emission from simple metals: Explicit calculations

Ja, Gaspar; Ag, Eguiluz; Dl, Mills

doi:10.1103/physrevb.51.14604

Cited by 9 publications

(4 citation statements)

References 8 publications

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“…In addition, the most common plasmon decay mechanism, a single-electron transition, can contribute to the emission of electrons from the solid. 2,3 Although plasmon excitation of metals by fast ions has attracted several theoretical studies, [3][4][5][6] experimental work for fast ion impact at energies of tens and hundreds of keV ͑Refs. 7-11͒ has been limited to identifying the plasmon decay structures seen in the electron emission spectra.…”

Section: Introductionmentioning

confidence: 99%

Proton-induced kinetic plasmon excitation in Al and Mg

1999

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We report energy distributions of electrons emitted from Al and Mg surfaces bombarded by 3-100-keV/amu hydrogen and deuterium ions. The energy spectra contain structure consistent with the decay of bulk plasmons, even below the velocity threshold expected from current theories. To explain the results we compare the importance of additional mechanisms involving electron capture, lattice-assisted excitation, and excitation by fast secondary electrons. ͓S0163-1829͑99͒02423-6͔

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Section: Introductionmentioning

confidence: 99%

Proton-induced kinetic plasmon excitation in Al and Mg

1999

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“…That electron-gas dispersion allows external probes to interact with bulk plasmons was discussed by Barton [4] and Eguiluz [5], and more recently by Nazarov et al [6]. Nevertheless, the fact that within a non-local description of screening bulk plasmons do give rise to a potential outside the solid has been ignored over the years [7,8], even when electrongas dispersion has been included; also, current non-local theories of plasmon excitation by external charges have not shown evidence for bulk plasmon excitation outside the solid [8][9][10]. Recently, Baragiola and Dukes [11] have studied the emission spectra produced by slow ions that were incident at grazing angle; their data indicate that the bulk plasmon is importantly involved in the emission process, though the projectiles are not expected to have penetrated into the solid.…”

mentioning

confidence: 99%

“…(8) and (9) in the Heisenberg picture. Our results [23] reproduce previous calculations for the image potential [defined as half the induced potential at the position of the charged particle that creates it] of a static (v = 0) external charged particle [5], which in the case of a non-dispersive electron gas (β = 0) coincides with the classical image potential [24] V im (z) = −(4z) −1 .…”

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confidence: 99%

Plasmon excitation by charged particles interacting with metal surfaces

1999

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Recent experiments (R. A. Baragiola and C. A. Dukes, Phys. Rev. Lett. 76, 2547 (1996)) with slow ions incident at grazing angle on metal surfaces have shown that bulk plasmons are excited under conditions where the ions do not penetrate the surface, contrary to the usual statement that probes exterior to an electron gas do not couple to the bulk plasmon. We here use the quantized hydrodynamic model of the bounded electron gas to derive an explicit expression for the probability of bulk plasmon excitation by external charged particles moving parallel to the surface. Our results indicate that for each q (the surface plasmon wave vector) there exists a continuum of bulk plasmon excitations, which we also observe within the semi-classical infinite-barrier (SCIB) model of the surface.It is well known that charged particles interacting with solid surfaces can create electronic collective excitations in the solid. These are bulk [1] and surface [2] plasmons. In the absence of electron-gas dispersion, the scalar electric potential due to bulk plasmons vanishes outside the surface [3]; hence, in this case probes exterior to the solid can only generate surface excitations. That electron-gas dispersion allows external probes to interact with bulk plasmons was discussed by Barton [4] and Eguiluz [5], and more recently by Nazarov et al [6]. Nevertheless, the fact that within a non-local description of screening bulk plasmons do give rise to a potential outside the solid has been ignored over the years [7,8], even when electrongas dispersion has been included; also, current non-local theories of plasmon excitation by external charges have not shown evidence for bulk plasmon excitation outside the solid [8][9][10]. Recently, Baragiola and Dukes [11] have studied the emission spectra produced by slow ions that were incident at grazing angle; their data indicate that the bulk plasmon is importantly involved in the emission process, though the projectiles are not expected to have penetrated into the solid. Bulk plasmon excitation in electron emission spectra produced by slow multiply charged ions has also been investigated [12], with projectiles that may enter the solid.In this letter we derive, within the quantized hydrodynamic model of the bounded electron gas [13], an explicit expression for the probability of bulk plasmon excitation by external charged particles moving parallel to a jellium surface. Our model, which assumes a sharp electron density profile at the surface, neatly displays the role of bulk plasmon excitations in the interaction of charged particles moving near a metal surface. We also demonstrate that our results for the total energy-loss probability agree with standard calculations [14] derived either by solving the linearized Bloch hydrodynamic equations [15] or within the semi-classical infinite-barrier (SCIB) model of the surface [16,17] with the hydrodynamic approximation for the bulk dielectric function. Though it has been generally believed that when charged particles move outside the solid the energy l...

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“…In addition to the few experimental studies of plasmon excitation of metals by fast ions, several theoretical studies have been made to obtain excitation rates vs and energy distributions of electrons from plasmon decay. [13][14][15][16][17][18] The usual electron gas description of valence electrons leads to a minimum or threshold velocity th for plasmon excitations by a moving charge, determined by conservation of energy and momentum. 13 For ions with mass much higher than the electron mass, the threshold velocity for exciting a narrow plasmon resonance is th Ϸ1.3 F .…”

Section: Introductionmentioning

confidence: 99%

Excitation of volume plasmons in glancing collisions of protons with Al(111) surfaces

et al. 2000

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We studied electron emission from Al͑111͒ surfaces induced by 4-100 keV protons at glancing incidence. The electron energy distributions show a structure due to the decay of volume plasmons. The intensity of the plasmon structure was measured as a function of angle of incidence to the surface. We found that volume plasmons are excited even under conditions where protons do not enter in the solid. The results are consistent with an indirect excitation mechanism by fast secondary electrons produced in binary ion-electron collisions. This mechanism is more important than direct excitations by ions and excitations produced by Auger electrons.

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Theory of ion-stimulated electron emission from simple metals: Explicit calculations

Cited by 9 publications

References 8 publications

Proton-induced kinetic plasmon excitation in Al and Mg

Proton-induced kinetic plasmon excitation in Al and Mg

Plasmon excitation by charged particles interacting with metal surfaces

Excitation of volume plasmons in glancing collisions of protons with Al(111) surfaces

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