Limits...
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) Comparison of our calculation of the total SPE cross section with the calculations from Colavita et al.50 and the experiment from Reinköster et al.51 on the absolute scale. (b) EELS spectra computed with our model response function eq. (2) (symbols) compared to experimental data33 (solid lines) for different scattering angles θ. The prefactor between theory and experiment was fixed for θ = 3° and kept constant for θ = 4° and θ = 5°.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4834545&req=5

f4: (a) Comparison of our calculation of the total SPE cross section with the calculations from Colavita et al.50 and the experiment from Reinköster et al.51 on the absolute scale. (b) EELS spectra computed with our model response function eq. (2) (symbols) compared to experimental data33 (solid lines) for different scattering angles θ. The prefactor between theory and experiment was fixed for θ = 3° and kept constant for θ = 4° and θ = 5°.

Mentions: Equation (3) is derived from the diagrammatic approach to photoemission28 based on the nonequilibrium Green’s function formalism. The full derivation is presented in the supplementary information. For an ab initio implementation of eq. (3) we rely on density functional theory (DFT) to compute the Kohn-Sham (KS) bound orbitals and their energies . We used the local density approximation (LDA) with self-interaction corrections. They improve the asymptotic behavior of the KS potential that is utilized to compute scattering states. The IPs and the core rearrangement shift Δ enter as experimentally determined4448. The SPE cross section is computed by the driven-scattering approach49, yielding excellent agreement with literature data5051 in the relevant energy range [Fig. 4(a)] of  eV. Note that incorporating many-body effects is not required here (as they mainly influence the cross section around the plasmon resonances). The multipolar plasmon modes entering eq. (2) needed for computing the effective interaction (1) is parameterized according to previous calculations30 and tested against EELS measurements in Fig. 4(b). Describing the Auger spectrum in Fig. 1(b) simply by the JDOS, thus neglecting plasmonic and other correlation effects, is justified by the large kinetic energy of the Auger electron, ruling out matrix-element effects in the considered energy window. Particularly, dynamical screening effects are strongly suppressed for a swift Auger electron due to the momentum-dependence of the density-density response function.


Electron pair escape from fullerene cage via collective modes.

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

(a) Comparison of our calculation of the total SPE cross section with the calculations from Colavita et al.50 and the experiment from Reinköster et al.51 on the absolute scale. (b) EELS spectra computed with our model response function eq. (2) (symbols) compared to experimental data33 (solid lines) for different scattering angles θ. The prefactor between theory and experiment was fixed for θ = 3° and kept constant for θ = 4° and θ = 5°.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: (a) Comparison of our calculation of the total SPE cross section with the calculations from Colavita et al.50 and the experiment from Reinköster et al.51 on the absolute scale. (b) EELS spectra computed with our model response function eq. (2) (symbols) compared to experimental data33 (solid lines) for different scattering angles θ. The prefactor between theory and experiment was fixed for θ = 3° and kept constant for θ = 4° and θ = 5°.
Mentions: Equation (3) is derived from the diagrammatic approach to photoemission28 based on the nonequilibrium Green’s function formalism. The full derivation is presented in the supplementary information. For an ab initio implementation of eq. (3) we rely on density functional theory (DFT) to compute the Kohn-Sham (KS) bound orbitals and their energies . We used the local density approximation (LDA) with self-interaction corrections. They improve the asymptotic behavior of the KS potential that is utilized to compute scattering states. The IPs and the core rearrangement shift Δ enter as experimentally determined4448. The SPE cross section is computed by the driven-scattering approach49, yielding excellent agreement with literature data5051 in the relevant energy range [Fig. 4(a)] of  eV. Note that incorporating many-body effects is not required here (as they mainly influence the cross section around the plasmon resonances). The multipolar plasmon modes entering eq. (2) needed for computing the effective interaction (1) is parameterized according to previous calculations30 and tested against EELS measurements in Fig. 4(b). Describing the Auger spectrum in Fig. 1(b) simply by the JDOS, thus neglecting plasmonic and other correlation effects, is justified by the large kinetic energy of the Auger electron, ruling out matrix-element effects in the considered energy window. Particularly, dynamical screening effects are strongly suppressed for a swift Auger electron due to the momentum-dependence of the density-density response function.

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