Physics / Fizik

Permanent URI for this collectionhttps://hdl.handle.net/11147/6

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Author: search.filters.author.Modarresi, MohsenLanguage: search.filters.language.en

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Now showing 1 - 2 of 2
  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Effects of Interedge Scattering on the Wigner Crystallization in Graphene Nanoribbons
    (American Physical Society, 2017) Modarresi, Mohsen; Güçlü, Alev Devrim
    We investigate the effects of coupling between the two zigzag edges of graphene nanoribbons on the Wigner crystallization of electrons and holes using a combination of tight-binding, mean-field Hubbard and many-body configuration interaction methods. We show that the thickness of the nanoribbon plays a crucial role in the formation of Wigner crystal. For ribbon widths smaller than 16 Å, increased kinetic energy overcomes the long-range Coulomb repulsion and suppresses the Wigner crystallization. For wider ribbons up to 38 Å wide, strong Wigner localization is observed for an even number of electrons, revealing an even-odd effect also found in the Coulomb-blockade addition spectrum. Interedge correlations are found to be strong enough to allow simultaneous crystallization on both edges, although an applied electric field can decouple the two edges. Finally, we show that Wigner crystallization can also occur for holes, albeit weaker than for electrons.
  • Article
    Citation - WoS: 57
    Citation - Scopus: 61
    Electronic and Optical Properties of Bilayer Blue Phosphorus
    (Elsevier Ltd., 2016) Moğulkoç, Yeşim; Modarresi, Mohsen; Moğulkoç, Aybey; Çiftci, Yasemin
    We investigate the electronic and optical properties of monolayer and stacking dependent bilayer blue phosphorus in the framework of density functional theory (DFT) and tight-binding approximations. We extract the hopping parameters of TB Hamiltonian for monolayer and bilayer blue phosphorus by using the DFT results. The variation of energy band gap with applied external electric field for two different stacks of bilayer blue phosphorus are also shown. We examine the linear response of the systems due to the external electromagnetic radiation in terms of the dielectric functions in the DFT theory. The relatively large electronic band gap and possibility of exfoliation form bulk structure due to weak interlayer coupling, make blue phosphorus an appropriate candidate for future electronic devices.