Strong-coupling theory of bilayer plasmon excitations

Fuente: arXiv
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Main Authors: Yamase, Hiroyuki, Zinni, Luciano, Bejas, Matías, Greco, Andrés
Format: Preprint
Published: 2025
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author Yamase, Hiroyuki
Zinni, Luciano
Bejas, Matías
Greco, Andrés
author_facet Yamase, Hiroyuki
Zinni, Luciano
Bejas, Matías
Greco, Andrés
contents Recently plasmon excitations in bilayer lattice systems were studied extensively in the weak-coupling regime. Unlike single-layer systems, these bilayers exhibit two distinct modes, $ω_{\pm}$, which show characteristic dependences upon the momentum and hopping integrals along the $z$ direction. To apply them to cuprates, strong correlation effects should be considered, but a comprehensive analysis has not yet been investigated. In this work, we present a strong-coupling theory to analyze the charge dynamics of a bilayer system, utilizing the $t$-$J$-$V$ model, which includes the long-range Coulomb interaction, $V$, on a lattice. Although our theoretical framework is fundamentally different from the weak-coupling approach, we find that resulting plasmon excitations are similar to those of a weak-coupling theory. A key distinction is that our strong-coupling framework reveals a noticeable suppression of particle-hole excitations, which allows the plasmon modes to remain well-defined over a wider region of momentum. We suggest that the experimentally reported plasmon excitations in Y-based cuprates can be described by the $ω_{-}$ mode, although we call for more systematic experiments to verify this.
format Preprint
id arxiv_https___arxiv_org_abs_2511_20776
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Strong-coupling theory of bilayer plasmon excitations
Yamase, Hiroyuki
Zinni, Luciano
Bejas, Matías
Greco, Andrés
Strongly Correlated Electrons
Recently plasmon excitations in bilayer lattice systems were studied extensively in the weak-coupling regime. Unlike single-layer systems, these bilayers exhibit two distinct modes, $ω_{\pm}$, which show characteristic dependences upon the momentum and hopping integrals along the $z$ direction. To apply them to cuprates, strong correlation effects should be considered, but a comprehensive analysis has not yet been investigated. In this work, we present a strong-coupling theory to analyze the charge dynamics of a bilayer system, utilizing the $t$-$J$-$V$ model, which includes the long-range Coulomb interaction, $V$, on a lattice. Although our theoretical framework is fundamentally different from the weak-coupling approach, we find that resulting plasmon excitations are similar to those of a weak-coupling theory. A key distinction is that our strong-coupling framework reveals a noticeable suppression of particle-hole excitations, which allows the plasmon modes to remain well-defined over a wider region of momentum. We suggest that the experimentally reported plasmon excitations in Y-based cuprates can be described by the $ω_{-}$ mode, although we call for more systematic experiments to verify this.
title Strong-coupling theory of bilayer plasmon excitations
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2511.20776