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arXiv · 1606.08573

The GW plus cumulant method and plasmonic polarons: application to the homogeneous electron gas

Fabio Caruso·Feliciano Giustino
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Abstract

We study the spectral function of the homogeneous electron gas using many-body perturbation theory and the cumulant expansion. We compute the angle-resolved spectral function based on the GW approximation and the `GW plus cumulant' approach. In agreement with previous studies, the GW spectral function exhibits a spurious plasmaron peak at energies 1.5$\omega_{\rm pl}$ below the quasiparticle peak, $\omega_{\rm pl}$ being the plasma energy. The GW plus cumulant approach, on the other hand, reduces significantly the intensity of the plasmon-induced spectral features and renormalizes their energy relative to the quasiparticle energy to $\omega_{\rm pl}$. Consistently with previous work on semiconductors, our results show that the HEG is characterized by the emergence of plasmonic polaron bands, that is, broadened replica of the quasiparticle bands, red-shifted by the plasmon energy.

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Fabio Caruso, Feliciano Giustino. 2016-06-28. The GW plus cumulant method and plasmonic polarons: application to the homogeneous electron gas. https://doi.org/10.1140/epjb/e2016-70028-4

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