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

• Published in: The European physical journal. B, Condensed matter physics Vol. 89; no. 11; pp. 1 - 7
• Main Authors: Caruso, Fabio, Giustino, Feliciano
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2016; Springer; Springer Nature B.V
• Subjects: Colloquium; Complex Systems; Condensed Matter Physics; Electrons; Fluid- and Aerodynamics; Methods; Physics; Physics and Astronomy; Plasmonics; Plasmons; Semiconductors (Materials); Solid State Physics; Topical issue: Ψk Volker Heine Young Investigator Award – 2015 Finalists
• ISSN: 1434-6028; 1434-6036
• DOI: 10.1140/epjb/e2016-70028-4

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 ω pl below the quasiparticle peak, ω 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 ω 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.