Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

Browse

Filters

2016 - 20182

Settings

Subject: search.filters.subject.Quantum dotsWoS Q: search.filters.wosQuartile.Q3

Search Results

Now showing 1 - 2 of 2
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Monolayer Aste2: Stable Robust Metal in 2d, 1d and 0d
    (Wiley, 2018) Badalov, S. V.; Kandemir, Ali; Şahin, Hasan
    The structural, phononic, and electronic properties of the monolayer structures of AsTe2 are characterized by performing density functional theory (DFT) calculations. Total energy optimization and phonon calculations reveal that single layers of the 2H-AsTe2 and 1T-AsTe2 phases form dynamically stable crystal structures. Electronic structure analysis also shows that both 2H and 1T phases have nonmagnetic metallic character. It is also predicted that the metallic nature of the ultra-thin both 2H-AsTe2 and 1T-AsTe2 structures remain unchanged even under high biaxial strain values. For further examination of the dimensionality effect in the robust metallicity in 2D AsTe2 phases, electronic characteristics of 1D nanoribbons and 0D quantum dots are also investigated. It is found that independent from the dimension and crystallographic orientations 0D and 1D structures of 2H- and 1T-AsTe2 structures have metallic behavior. It is found that single layers of AsTe2 are quite promising materials for nanodevice applications owing to the robust metallic character.
  • Article
    Citation - WoS: 26
    Citation - Scopus: 26
    Theory of Optical Properties of Graphene Quantum Dots
    (John Wiley and Sons Inc., 2016) Özfidan, Işıl; Güçlü, Alev Devrim; Korkusinski, Marek; Hawrylak, Pawel
    We present here a theory of the optical properties of graphene quantum dots (GQDs) with tunable band gaps by lateral size confinement, from UV to THz. Starting from the Hartree-Fock ground state, we construct the correlated many-body ground and excited states of GQDs as a linear combination of a finite number of electron-hole pair excitations. We discuss the evolution of the band gap with size and its renormalization by self-energy and excitonic effects. We calculate and analyze the dipole moments of graphene quantum dots that possess a degenerate valence and conduction band edge, and construct a characteristic exciton and biexciton spectrum. We find an exciton band consisting of a pair of robust, spin singlet bright exciton states and a band of dark, spin singlet and spin triplet, exciton states at lower energies. We predict a characteristic band of biexciton levels at the band edge, discuss the Auger processes and identify a biexciton-exciton cascade. Our theoretical results are compared with experimental linear absorption and non-linear transient absorption spectra of colloidal GQDs. We next discuss the optical properties of triangular GQDs with zigzag edges whose magnetic moment can be controlled by gates. The control over the magnetic moment through carrier density manipulation results in optical spin blockade and gate tunable optical properties over a wide range of photon energies.