p. sahebsara

In this research, localized surface plasmon resonance spectra for single spherical gold nanoparticles with radius between 20 to 55nm in environments of different refractive indices between 1 and 1.8 has been studied by Finite Different Time Domain method. In this simulations, plasmon resonance frequency is determined for each nanoparticle with optimized mesh size, and is compared with the results of Mie theory. Moreover, using these results, plasmonic propertis of gold nanoshells of various diameters were studied in air (n=1) and water (n=1.33). Plasmon resonance has been calculated for nanoshells and it was concluded that in different environments, gold nanoshells with outer radius of 20 nanometers and diameter of 12 nanometers have their plasmonic spectrum are associated on gold nanosphere with the same outer radius.  frequency for nanoshells has been calculated. The plasmon resonance peak shift for various nanoparticles is plotted versus refractive indices. Finally, the most sensitive and most insennitive of nanoparticles to the refractive index of the environment has been discussed for sensing applications.

The possibility of symmetrical s-wave superconductivity in the honeycomb lattice is studied within a strongly correlated regime، using the Hubbard model. The superconducting order parameter is defined by introducing the Green function، which is obtained by calculating the density of the electrons ‎. In this study showed that the superconducting order parameter appears in doping interval between 0 and 0. 5، and x=0. 25 is the optimum doping for the s-wave superconductivity in honeycomb lattice.