Resolving the Mechanism of Acoustic Plasmon Instability in Graphene Doped by Alkali Metals

Autor: Leonardo Marušić, Ana Kalinić, Ivan Radović, Josip Jakovac, Zoran L. Mišković, Vito Despoja
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: International Journal of Molecular Sciences, Vol 23, Iss 9, p 4770 (2022)
Druh dokumentu: article
ISSN: 1422-0067
1661-6596
DOI: 10.3390/ijms23094770
Popis: Graphene doped by alkali atoms (ACx) supports two heavily populated bands (π and σ) crossing the Fermi level, which enables the formation of two intense two-dimensional plasmons: the Dirac plasmon (DP) and the acoustic plasmon (AP). Although the mechanism of the formation of these plasmons in electrostatically biased graphene or at noble metal surfaces is well known, the mechanism of their formation in alkali-doped graphenes is still not completely understood. We shall demonstrate that two isoelectronic systems, KC8 and CsC8, support substantially different plasmonic spectra: the KC8 supports a sharp DP and a well-defined AP, while the CsC8 supports a broad DP and does not support an AP at all. We shall demonstrate that the AP in an ACx is not, as previously believed, just a consequence of the interplay of the π and σ intraband transitions, but a very subtle interplay between these transitions and the background screening, caused by the out-of-plane interband C(π)→A(σ) transitions.
Databáze: Directory of Open Access Journals
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