Excitonic Effects in Energy-Loss Spectra of Freestanding Graphene.

Autor: Guandalini A; S3 Centre, Istituto Nanoscienze, CNR, Via Campi 213/a, 41125 Modena, Italy.; Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy., Senga R; Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan., Lin YC; Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan., Suenaga K; Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan.; The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan., Ferretti A; S3 Centre, Istituto Nanoscienze, CNR, Via Campi 213/a, 41125 Modena, Italy., Varsano D; S3 Centre, Istituto Nanoscienze, CNR, Via Campi 213/a, 41125 Modena, Italy., Recchia A; Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy.; Center for Life NanoScience, Istituto Italiano di Tecnologia, viale Regina Elena 291, 00161 Rome, Italy., Barone P; Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy.; CNR-SPIN, Area della Ricerca di Tor Vergata, Via del Fosso del Cavaliere 100, I-00133 Rome, Italy., Mauri F; Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy., Pichler T; University of Vienna, Faculty of Physics, Strudlhofgasse 4, A1090 Vienna, Austria., Kramberger C; University of Vienna, Faculty of Physics, Strudlhofgasse 4, A1090 Vienna, Austria.
Jazyk: angličtina
Zdroj: Nano letters [Nano Lett] 2023 Dec 27; Vol. 23 (24), pp. 11835-11841. Date of Electronic Publication: 2023 Dec 13.
DOI: 10.1021/acs.nanolett.3c03863
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 to ab initio calculations at increasing levels of theory. Quasi-particle corrections and excitonic effects are addressed within the GW approximation and the 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 π plasmon being significantly affected by excitonic effects.
Databáze: MEDLINE
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