Encontrados 15 documentos, a visualizar página 1 de 2
A primer on surface plasmon-polaritons in graphene
Bludov, Yuliy V.; Ferreira, Aires; Peres, N. M. R.; Vasilevskiy, MikhailWe discuss the properties of surface plasmons-polaritons in graphene and describe four possible ways of coupling electromagnetic radiation in the terahertz (THz) spectral range to this type of surface waves: (i) the attenuated total reflection (ATR) method us- ing a prism in the Otto configuration, (ii) graphene micro-ribbon arrays or monolayers with modulated conductivity, (iii) a metal stripe on top of the gr...
Exact solution for square-wave grating covered with graphene : surface plasmons...
Peres, N. M. R.; Bludov, Yuliy V.; Ferreira, Aires; Vasilevskiy, MikhailWe provide an analytical solution to the problem of scattering of electromagnetic radiation by a square-wave grating with a flat graphene sheet on top.We show that for deep groves there is a strong plasmonic response, with light absorption in the graphene sheet reaching more than 45% due to the excitation of surface plasmon-polaritons. The case of a grating with a graphene sheet presenting an induced periodic m...
Light scattering by a medium with a spatially modulated optical conductivity : ...
Peres, N. M. R.; Ferreira, Aires; Bludov, Yuliy V.; Vasilevskiy, MikhailWe describe light scattering from a graphene sheet having a modulated optical conductivity. We show that such modulation enables the excitation of surface plasmon polaritons by an electromagnetic wave impinging at normal incidence. The resulting surface plasmon polaritons are responsible for a substantial increase of electromagnetic radiation absorption by the graphene sheet. The origin of the modulation can be...
Efficient graphene-based photodetector with two cavities
Ferreira, Aires; Peres, N. M. R.; Ribeiro, R. M.; Stauber, TobiasDocumento submetido para revisão pelos pares a publicar em Physical Review B. ; We present an efficient graphene-based photodetector with two Fabri-P\'erot cavities. It is shown that the absorption can reach almost 100% around a given frequency, which is determined by the two-cavity lengths. It is also shown that hysteresis in the absorbance is possible, with the transmittance amplitude of the mirrors working ...
Confined magneto-optical waves in graphene
Ferreira, Aires; Peres, N. M. R.; Castro Neto, A. H.The electromagnetic mode spectrum of single-layer graphene subjected to a quantizing magnetic field is computed taking into account intraband and interband contributions to the magneto-optical conductivity. We find that a sequence of weakly decaying quasi-transverse-electric modes, separated by magnetoplasmon polariton modes, emerge due to the quantizing magnetic field. The characteristics of these modes are tu...
Complete light absorption in graphene-metamaterial corrugated structures
Ferreira, Aires; Peres, N. M. R.We show that surface-plasmon polaritons excited in negative permittivity metamaterials having shallow periodic surface corrugation profiles can be explored to push the absorption of single and continuous sheets of graphene up to 100%. In the relaxation regime, the position of the plasmonic resonances of the hybrid system is determined by the plasma frequency of the metamaterial, allowing the frequency range for...
Unified description of the DC conductivity of monolayer and bilayer graphene ba...
Ferreira, Aires; Nilsson, Johan; Castro Neto, A. H.; Gomes, J. Viana; Peres, N. M. R.We show that a coherent picture for the DC conductivity of monolayer and bilayer graphene emerges from considering that strong short-range potentials are the main source of scattering in these two systems. The origin of the strong short range potentials may lie in adsorbed hydrocarbons at the surface of graphene. The equivalence between results based on the partial wave description of scattering and the T-matri...
Transport properties of graphene with one-dimensional charge de- fects
Ferreira, Aires; Chang-Lin Tan; Peres, N. M. R.; Ozyilmaz, Barbaros; Xiangfan Xu; Su-Kang Bae; Byung-Hee Hong; Castro Neto, A. H.We study the e ect of extended charge defects in electronic transport properties of graphene. Extended defects are ubiquitous in chemically and epitaxially grown graphene samples due to internal strains associated with the lattice mismatch. We show that at low energies these defects interact quite strongly with the 2D Dirac fermions and have an important ef ect in the DC-conductivity of these materials.
Factores climáticos no consumo de energia eléctrica: um caso com utilização de ...
Mendes, Armando B.; Ferreira, José M. S.; Ferreira, Aires4ª Conferência Ibérica de Sistemas e Tecnologias de Informação, 17 a 20 de Junho de 2009, Póvoa de Varzim. ; Este trabalho tem por objectivo identificar causas responsáveis por variações no consumo horário de energia com base na identificação de padrões e relações entre os dados de consumo e várias variáveis climatéricas. Para tal utilizam-se técnicas de data mining, nomeadamente a metodologia CRISP-DM e softw...
Desempenho agronômico de cultivares de mamona no Rio Grande do Sul.
Rogério Ferreira AiresA demanda por informações técnicas sobre a cultura da mamona no RS, se intensificou nos últimos dois anos, devido ao estímulo do governo para a produção de biocombustíveis, pelas diversas aplicações do óleo de mamona na indústria química e farmacêutica e pelos índices de produtividade alcançados pela cultura da mamona em ensaios e lavouras experimentais. Sem dúvida a cultura é uma alternativa para a diversifica...
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