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We calculate the plasmon dispersion relation and damping rate of collective excitations in a double-layer system consisting of monolayer graphene and GaAs quantum well at zero temperature including layer-thickness and exchangecorrelation effects. We use the generalized random-phase-approximation dielectric function and take into account the nonhomogeneity of the dielectric background of the system. We show that the effects of layer thickness, electron densities, and exchange-correlations are more pronounced for acoustic modes, while the optical branch depends remarkably on dielectric constants of the contacting media. Key words: graphene, plasmon, collective excitations, double-layer systems, electron gas. Nous incluons les effets d'epaisseur de couche et d'echange-correlation pour calculer la relation de dispersion et le taux d'amortissement des excitations collectives dans un systeme a deux couches, consistant en une monocouche de graphene et un puits quantique GaAs a temperature zero. Nous utilisons la fonction dielectrique de l'approximation par phases aleatoires generalisee et nous tenons compte de la non homogeneite du fond dielectrique du systeme. Nous montrons que les effets d'epaisseur de couche, de densite electronique sont plus prononces pour les modes acoustiques, alors que la branche optique depend beaucoup de la constante dielectrique du milieu de contact. [Traduit par la Redaction] Mots-cles: graphene, plasmon, excitations collectives, systeme a deux couches, gaz d'electrons., 1. Introduction Graphene, a special two-dimensional electron gas (2DEG) system, has attracted a great deal of attention in recent years because of its unique electronic properties [1-3]. Charge carriers in [...]

We present a simple and intuitive picture, an electromagnetic analog of molecular orbital theory, that describes the plasmon response of complex nanostructures of arbitrary shape. Our model can be understood as the interaction or 'hybridization' of elementary plasmons supported by nanostructures of elementary geometries. As an example, the approach is applied to the important case of a four-layer concentric nanoshell, where the hybridization of the plasmons of the inner and outer nanoshells determines the resonant frequencies of the multilayer nanostructure., The fabrication of materials on a nanoscale can be used to enhance and exploit properties that become stronger under conditions of reduced dimensionality. In metallic systems, the conduction electron charge [...]

The time dynamics of excitation and dephasing of circularly polarized plasmon modes in spherical nanoshells is analyzed. The analytical formulas are given for steady-state amplitudes of these modes for resonance and off-resonance excitations.