Electron Scattering at Steps: Image-Potential States on Cu(119)

Roth, Manfred; Pickel, M.; Wang, Jinxiong; Weinelt, Martin; Fauster, Thomas

doi:10.1103/physrevlett.88.096802

Cited by 68 publications

(48 citation statements)

References 19 publications

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“…41) come close to the latest calculations [69]. The remaining discrepancy can be attributed to the residual step density on the sample which leads to an efficient resonant interband scattering to the n ¼ 1 band [232,234,235] and an apparent reduction of the measured lifetimes for the higher image-potential states.…”

Section: Image-potential Statesmentioning

confidence: 49%

“…For Cu(1 1 1) a strong increase of the dephasing with temperature is found [221,244]. The almost equal strength of decay and dephasing for the n ¼ 1 image-potential state on Cu (1 1 7) is most likely attributed to disorder in the step separation [234,235,248]. For CO and Cu on copper substrates the change of the respective rates with coverage is given.…”

Section: Influence Of Defectsmentioning

confidence: 99%

“…Accordingly, the decay rates differ by approximately one order of magnitude. For the stepped copper surfaces Cu (1 1 7) or Cu(1 1 9) the decay rates of the higher image-potential states contain a significant contribution from the interband scattering into lower image-potential bands at the same energy but at a different momentum [234,244]. The decay due to electron-electron scattering with bulk or surface electrons would therefore be close to the Cu(0 0 1) line.…”

Section: Linewidths Of Image-potential Statesmentioning

confidence: 99%

“…This interband scattering can be mediated by defects [222,233]. Systematic studies on vicinal surfaces have shown that steps are particularly efficient sources for this resonant interband scattering between image-potential states of different quantum numbers [234,235]. Theoretically, these quasielastic scattering processes are not as (1 1 1).…”

Section: Momentum Dependence Of Lifetimesmentioning

confidence: 99%

See 3 more Smart Citations

Decay of electronic excitations at metal surfaces

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et al. 2004

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Section: Image-potential Statesmentioning

confidence: 49%

Section: Influence Of Defectsmentioning

confidence: 99%

Section: Linewidths Of Image-potential Statesmentioning

confidence: 99%

Section: Momentum Dependence Of Lifetimesmentioning

confidence: 99%

See 2 more Smart Citations

Decay of electronic excitations at metal surfaces

Echenique

Berndt

Chulkov

et al. 2004

Surface Science Reports

438

403

View full text Add to dashboard Cite

“…48 This interband scattering process is promoted by steps or surface defects as has been systematically studied by Fauster and Weinelt. [49][50][51] Since the relative signal arising from this processes is very small, the deduced momentum dependent scattering rates are not affected by this process. Figure 7 summarizes the results for Cu(100) and shows the momentum-dependent decay rates for one monolayer Krypton and Argon in comparison with the previous results on the clean surface.…”

Section: B Rare-gas Covered Surfacesmentioning

confidence: 99%

Momentum-resolved electron dynamics of image-potential states on Cu and Ag surfaces

et al. 2012

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The dependence of the inelastic lifetime of electrons in the first n = 1 image-potential state of clean and rare-gas covered Ag(111), Cu(111), and Cu(100) surfaces on their momentum parallel to the surface has been studied experimentally by means of time-and angle-resolved two-photon photoemission spectroscopy (2PPE) and theoretically by calculations based on the many-body theory within the self-energy formalism. Similar to the previously studied clean Cu(100) surface, the theoretical results are in excellent agreement with the experiment findings for Cu(111). For Ag(111), the theory overestimates the decay rate and its momentum dependence, which is attributed to the neglect of surface plasmon excitations. With increasing parallel momentum, the n = 1 state shifts out of the projected bulk band gap on both surfaces and turns into an image-potential resonance. This opens an additional decay channel by resonant electron transfer into the bulk, which is theoretically treated by the application of the wave packet propagation approach. The expected stronger increase of the decay rate upon crossing the edge of the band gap, however, is not observed in the experiment. The decoupling of the image-potential states from the metal surface upon adsorption of rare-gas layers results in a decrease of the decay rate as well as of its momentum dependence by a similar factor, which can be successfully explained by the change of interband and intraband contributions to the total decay rate.

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Time‐resolved two‐photon photoemission

Fauster¹

2003

Solid‐State Photoemission and Related Methods

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In this chapter time resolution will be introduced to photoemission experiments. This means not just a series of regular photoemission measurements to monitor the changes of a sample with time. In two-photon photoemission the time delay between the two photons is an additional experimental parameter which can be controlled with femtosecond resolution, i.e., on a time scale relevant for electronic processes. At the same time, the introduction of the second photon leads to the participation of an additional electronic state in the energy diagram for photoemission. Energy diagramIn Figure 8.1 the transition from initial state |1 to an intermediate state |2 after the absorption of the photon with energy hν a is shown. The second photon of energy hν b excites the electron out of the intermediate state into the final state |3 . If the final state energy E 3 is above the vacuum energy E vac , the electron might leave the surface and its kinetic energy E kin is measured with an electron energy analyzer. Obviously, the initial state has to be occupied, i.e., its energy E 1 should be below the Fermi energy E F . The intermediate state on the other hand has to be empty at first. In most cases it is desirable to keep the photon energy hν a below the work function Φ = E vac − E F , because this constitutes the threshold for one-photon photoemission. This applies also to the other photon, because processes with the role of the two photons interchanged are possible as well. Energy-resolved spectroscopyThe spectrum sketched at the right of Fig. 8.1 shows a peak at the final state energy E 3 . The cutoff at kinetic energy zero corresponds to the vacuum level E vac of the sample. Electrons with the highest energy after the absorption of the photons with energies hν a and hν b appear at kinetic energy E max − E vac = hν a + hν b − Φ. These limits are familiar from regular photoemission spectroscopy and can be used to determine the work function from the width of the spectrum. Similarly, the momentum k of the electron parallel to the surface is conserved for single-crystal surfaces. For electrons emitted at an angle ϑ with respect to the surface normal one obtainshk = √ 2mE kin sin ϑ. Umklapp processes would add reciprocal lattice vectors of the surface to the momentum conservation, but play usually no role in twophoton photoemission. One has to keep in mind that the kinetic energies are generally quite

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Electron Scattering at Steps: Image-Potential States on Cu(119)

Cited by 68 publications

References 19 publications

Decay of electronic excitations at metal surfaces

Decay of electronic excitations at metal surfaces

Momentum-resolved electron dynamics of image-potential states on Cu and Ag surfaces

Time‐resolved two‐photon photoemission

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