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Electron pair escape from fullerene cage via collective modes.

Schüler M, Pavlyukh Y, Bolognesi P, Avaldi L, Berakdar J - Sci Rep (2016)

Bottom Line: Experiment and theory evidence a new pathway for correlated two-electron release from many-body compounds following collective excitation by a single photon.Results from a full ab initio implementation for C60 fullerene are in line with experimental observations.The findings endorse the correlated two-electron photoemission as a powerful tool to access electronic correlation in complex systems.

View Article: PubMed Central - PubMed

Affiliation: Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany.

ABSTRACT
Experiment and theory evidence a new pathway for correlated two-electron release from many-body compounds following collective excitation by a single photon. Using nonequilibrium Green's function approach we trace plasmon oscillations as the key ingredient of the effective electron-electron interaction that governs the correlated pair emission in a dynamic many-body environment. Results from a full ab initio implementation for C60 fullerene are in line with experimental observations. The findings endorse the correlated two-electron photoemission as a powerful tool to access electronic correlation in complex systems.

No MeSH data available.


Related in: MedlinePlus

(a) Energy level scheme for DPE mediated by charge-density fluctuations in three steps: (i) A valence electron is photo-promoted to an intermediate state with energy . (ii) This electron scatters inelastically from excited C60 to an energy state  while creating multipolar plasmonic modes with energy ωpl that (iii) decay on the attosecond time scale52, leading to the coherent emission of a second electron (energy ) if ωpl is larger than the ionization potential (IP) of . (b) A cut through fullerene center of the calculated fluctuation densities ρνLM(r) of the symmetric (SS) and anti-symmetric (AS) surface plasmon modes. L(M) characterizes the multipolarity (and its azimuthal behavior) and ν is a radial quantum number (here M = 0). Colored regions represent ρνLM(r) > 5 × 10−4 a.u. (light orange) and ρνLM(r) < −5 × 10−4 a.u. (dark blue).
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f2: (a) Energy level scheme for DPE mediated by charge-density fluctuations in three steps: (i) A valence electron is photo-promoted to an intermediate state with energy . (ii) This electron scatters inelastically from excited C60 to an energy state while creating multipolar plasmonic modes with energy ωpl that (iii) decay on the attosecond time scale52, leading to the coherent emission of a second electron (energy ) if ωpl is larger than the ionization potential (IP) of . (b) A cut through fullerene center of the calculated fluctuation densities ρνLM(r) of the symmetric (SS) and anti-symmetric (AS) surface plasmon modes. L(M) characterizes the multipolarity (and its azimuthal behavior) and ν is a radial quantum number (here M = 0). Colored regions represent ρνLM(r) > 5 × 10−4 a.u. (light orange) and ρνLM(r) < −5 × 10−4 a.u. (dark blue).

Mentions: The emerging physical picture is illustrated in Fig. 2(a): (i) Photoabsorption promotes a valence electron to a high-energy state. (ii) This electron scatters inelastically from charge-density fluctuations (plasmon creation) that (iii) decay emitting a second valence electron (whose energy and angular correlations with the first one is measured in a coincidence set up, revealing so how charge-density fluctuations mediate e–e interaction). This three-step mechanism (3SM) emerges from a diagrammatic nonequilibrium Green’s function (NEGF) approach as detailed in the supplementary information. It is already clear at this stage that DPE is qualitatively different from SPE in that, a) it delivers information on e–e interaction mediated by charge-density fluctuations, and b) as these plasmonic excitations are triggered by an electron a multitude of modes, e.g. volume plasmons, are involved.


Electron pair escape from fullerene cage via collective modes.

Schüler M, Pavlyukh Y, Bolognesi P, Avaldi L, Berakdar J - Sci Rep (2016)

(a) Energy level scheme for DPE mediated by charge-density fluctuations in three steps: (i) A valence electron is photo-promoted to an intermediate state with energy . (ii) This electron scatters inelastically from excited C60 to an energy state  while creating multipolar plasmonic modes with energy ωpl that (iii) decay on the attosecond time scale52, leading to the coherent emission of a second electron (energy ) if ωpl is larger than the ionization potential (IP) of . (b) A cut through fullerene center of the calculated fluctuation densities ρνLM(r) of the symmetric (SS) and anti-symmetric (AS) surface plasmon modes. L(M) characterizes the multipolarity (and its azimuthal behavior) and ν is a radial quantum number (here M = 0). Colored regions represent ρνLM(r) > 5 × 10−4 a.u. (light orange) and ρνLM(r) < −5 × 10−4 a.u. (dark blue).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834545&req=5

f2: (a) Energy level scheme for DPE mediated by charge-density fluctuations in three steps: (i) A valence electron is photo-promoted to an intermediate state with energy . (ii) This electron scatters inelastically from excited C60 to an energy state while creating multipolar plasmonic modes with energy ωpl that (iii) decay on the attosecond time scale52, leading to the coherent emission of a second electron (energy ) if ωpl is larger than the ionization potential (IP) of . (b) A cut through fullerene center of the calculated fluctuation densities ρνLM(r) of the symmetric (SS) and anti-symmetric (AS) surface plasmon modes. L(M) characterizes the multipolarity (and its azimuthal behavior) and ν is a radial quantum number (here M = 0). Colored regions represent ρνLM(r) > 5 × 10−4 a.u. (light orange) and ρνLM(r) < −5 × 10−4 a.u. (dark blue).
Mentions: The emerging physical picture is illustrated in Fig. 2(a): (i) Photoabsorption promotes a valence electron to a high-energy state. (ii) This electron scatters inelastically from charge-density fluctuations (plasmon creation) that (iii) decay emitting a second valence electron (whose energy and angular correlations with the first one is measured in a coincidence set up, revealing so how charge-density fluctuations mediate e–e interaction). This three-step mechanism (3SM) emerges from a diagrammatic nonequilibrium Green’s function (NEGF) approach as detailed in the supplementary information. It is already clear at this stage that DPE is qualitatively different from SPE in that, a) it delivers information on e–e interaction mediated by charge-density fluctuations, and b) as these plasmonic excitations are triggered by an electron a multitude of modes, e.g. volume plasmons, are involved.

Bottom Line: Experiment and theory evidence a new pathway for correlated two-electron release from many-body compounds following collective excitation by a single photon.Results from a full ab initio implementation for C60 fullerene are in line with experimental observations.The findings endorse the correlated two-electron photoemission as a powerful tool to access electronic correlation in complex systems.

View Article: PubMed Central - PubMed

Affiliation: Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany.

ABSTRACT
Experiment and theory evidence a new pathway for correlated two-electron release from many-body compounds following collective excitation by a single photon. Using nonequilibrium Green's function approach we trace plasmon oscillations as the key ingredient of the effective electron-electron interaction that governs the correlated pair emission in a dynamic many-body environment. Results from a full ab initio implementation for C60 fullerene are in line with experimental observations. The findings endorse the correlated two-electron photoemission as a powerful tool to access electronic correlation in complex systems.

No MeSH data available.


Related in: MedlinePlus