Arama Sonuçları

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  • Yayın
    Magnetoresistivity of a weakly-screened, low-density, two-dimensional electron liquid
    (Physical Soc Japan, 2013-07) Karakurt, İsmail; Dahm, Arnold J.
    We probe the strength of electron-electron interactions at intermediate magnetic fields in the classical regime using magnetoconductivity measurements of two-dimensional, non-degenerate electrons on liquid helium. We span both the independent-electron regime, where the data are qualitatively described by the self-consistent Born approximation (SCBA), and the strongly-interacting electron (Drude) regime. We observe a crossover from SCBA to Drude theory at finite magnetic fields as a function of electron density. The SCBA magnetoresistance is found to be density dependent. Our data confirm the theory for magnetoresistivity in a weakly screened, two-dimensional electron gas, and demonstrate that electron-electron interactions are important to very low densities.
  • Yayın
    Particle size and shell thickness dependence of the light intensity enhancement in the cap layers of Ag, Au, Al and SiO2@TiO2 core-shell nanostructures
    (Wiley-V C H Verlag GMBH, 2018-03-22) Başcura, Erdem Berkay; Karakurt, İsmail
    We present a systematic study of the light intensity enhancement in the shell layers of half burrried Ag, Au, Al and SiO2 spherical nanoparticles capped with TiO2. We calculated the light intensity profiles near these structures when they are illuminated by a UV light at 380 nm. The calculations cover the particle-size range between 20 and 180 nm, and the cap thickness range between 6 and 80 nm. Our data is the first report on the intensity enhancement in the shell layers of TiO2-capped Al nanoparticles and Al@TiO2 core-shell nanostructures. We obtain, in the cap layers, an average intensity enhancement of similar to 3.7, similar to 6.1, similar to 2.4 and similar to 2.7 for a cap thickness of similar to 30nm above Ag, Al, Au and SiO2 particles. Taking into account the increase in the active surface area, these numbers can be multiplied by a factor of two, for each capped-nanoparticle system. The optimal Ag, Au, Al and SiO2-particle sizes for a 30-nm cap-thickness are found to be 120 nm, 80 nm, 140 nm, and 80 nm. While half-buried and capped-nanoparticle systems resemble the typical core-shell nanoparticles, the intensity enhancements are not equivalent. We compare the intensity increases in these two systems at the optimal sizes for Ag and Al particles for a 30-nm shell thickness.