446 research outputs found
Graphene-plasmon polaritons: From fundamental properties to potential applications
With the unique possibilities for controlling light in nanoscale devices,
graphene plasmonics has opened new perspectives to the nanophotonics community
with potential applications in metamaterials, modulators, photodetectors, and
sensors. This paper briefly reviews the recent exciting progress in graphene
plasmonics. We begin with a general description for optical properties of
graphene, particularly focusing on the dispersion of graphene-plasmon
polaritons. The dispersion relation of graphene-plasmon polaritons of spatially
extended graphene is expressed in terms of the local response limit with
intraband contribution. With this theoretical foundation of graphene-plasmon
polaritons, we then discuss recent exciting progress, paying specific attention
to the following topics: excitation of graphene plasmon polaritons,
electron-phonon interactions in graphene on polar substrates, and tunable
graphene plasmonics with applications in modulators and sensors. Finally, we
seek to address some of the apparent challenges and promising perspectives of
graphene plasmonics.Comment: Invited minireview paper on graphene plasmon polaritons, 11 pages, 4
figure
Steady and dynamic magnetic phase transitions in interacting quantum dots arrays coupled with leads
We apply the Hubbard model, non-equilibrium Green's function (NEGF) theory,
exact diagonalization (ED) and the hierarchical equations of motion (HEOM)
method to investigate abundant magnetic phase transitions in the 1D interacting
quantum dots arrays (QDA) sandwiched by non-interaction leads. The spin
polarization phase transitions are firstly studied with a mean-field
approximation. The many-body calculation of the ED method is then used to
verify such transitions. We find with the weak device-leading couplings, the
anti-ferromagnetic (AF) state only exists in the uniform odd-numbered QDA or
the staggered-hopping QDA systems. With increasing the coupling strength or the
bias potentials, there exists the magnetism-to non-magnetism phase transition.
With the spin-resolved HEOM method we also investigate the detailed dynamic
phase transition process of these lead-QDA-lead systems.Comment: 17 pages, 6 figure
Experimental observation of plasmons in a graphene monolayer resting on a two-dimensional subwavelength silicon grating
We experimentally demonstrate graphene-plasmon polariton excitation in a
continuous graphene monolayer resting on a two-dimensional subwavelength
silicon grating. The subwavelength silicon grating is fabricated by a
nanosphere lithography technique with a self-assembled nanosphere array as a
template. Measured transmission spectra illustrate the excitation of
graphene-plasmon polaritons, which is further supported by numerical
simulations and theoretical prediction of plasmonband diagrams. Our
grating-assisted coupling to graphene-plasmon polaritons forms an important
platform for graphene-based opto-electronics applications.Comment: 13 pages, 4 figures, revised version accepted by AP
Analytical solutions for fractional partial delay differential-algebraic equations with Dirichlet boundary conditions defined on a finite domain
In this paper, we investigate the solution of multi-term time-space fractional partial delay differential-algebraic equations (MTS-FPDDAEs) with Dirichlet boundary conditions defined on a finite domain. We use Laplace transform method to give the solutions of multi-term time fractional delay differential-algebraic equations (MTS-FDDAEs). Then, the technique of spectral representation of the fractional Laplacian operator is used to convert the MTS-FPDDAEs into the MTS-FDDAEs. By applying our obtained solutions to the resulting MTS-FDDAEs, the desired analytical solutions of the MTS-FPDDAEs are obtained. Finally, we give the solutions of some special casesThis work was supported by the Natural Science Foundation of China (NSFC) under grants 11871400. The work of J.J. Nieto has been partially supported by the Agencia Estatal de Investigacion (AEI) of Spain under Grant PID2020-113275GB-I00 and co-financed by European Community fund FEDER and by Xunta de Galicia, grant ED431C 2019/02. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer NatureS
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