Excitonic effects in energy loss spectra of freestanding graphene

Autor(en)

Alberto Guandalini, Ryosuke Senga, Yung-Chang Lin, Kazu Suenaga, Andrea Ferretti, Daniele Varsano, Andrea Recchia, Paolo Barone, Francesco Mauri, Thomas Pichler, Christian Kramberger

Abstrakt

In this work we perform electron energy-loss spectroscopy (EELS) of freestanding graphene with high energy and momentum resolution to disentangle the quasielastic scattering from the excitation gap of Dirac electrons close to the optical limit. We show the importance of many-body effects on electronic excitations at finite transferred momentum by comparing measured EELS with ab initio calculations at increasing levels of theory. Quasi-particle corrections and excitonic effects are addressed within the GW approximation and Bethe-Salpeter equation, respectively. Both effects are essential in the description of the EEL spectra to obtain a quantitative agreement with experiments, with the position, dispersion, and shape of both the excitation gap and the $\pi$ plasmon being significantly affected by excitonic effects.

Organisation(en)

Dynamik Kondensierter Systeme, Elektronische Materialeigenschaften

Externe Organisation(en)

Consiglio Nazionale delle Ricerche, Università degli Studi di Roma La Sapienza, National Institute of Advanced Industrial Science and Technology (AIST), Istituto italiano di tecnologia, Università degli Studi di Roma "Tor Vergata"

Journal

Nano Letters

Band

23

Seiten

11835–11841

Anzahl der Seiten

7

ISSN

1530-6984

DOI

https://doi.org/10.48550/arXiv.2302.06367

Publikationsdatum

11-2023

Peer-reviewed

Ja

ÖFOS 2012

103018 Materialphysik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/2403a065-3d0b-416b-b46c-7096e0bfe48e