Now showing items 1-13 of 13

    • Charged bosons in a quasi-one-dimensional system 

      Tanatar, Bilal; Davoudi, B.; Kohandel, M. (American Physical Society, 2000)
      The ground-state properties of a system of charged bosons in a quasi-one-dimensional model with a neutralizing background are investigated within the hypernetted-chain approximation. Strong correlation effects drive the ...
    • A comparative study of O2 adsorbed carbon nanotubes 

      Dag, S.; Gülseren, O.; Çıracı, Salim (2003)
      First-principles, density functional calculations show that O2 adsorbed single-wall carbon nanotubes (SWNT) show dramatic differences depending on the type of the tube. Upon O2 physisorption, the zig-zag SWNT remains ...
    • Electronic structure of Te-and As-covered Si(211) 

      Sen, P.; Batra, I. P.; Sivananthan, S.; Grein, C. H.; Dhar, N.; Çıracı, Salim (American Physical Society, 2003)
      Electronic and atomic structures of the clean and As- and Te-covered Si(211) surface are studied using pseudopotential density-functional method. The clean surface is found to have (2 x 1) and rebonded (1 x 1) reconstructions ...
    • Formation of quantum structures on a single nanotube by modulating hydrogen adsorption 

      Gülseren, O.; Yildirim, T.; Çıracı, Salim (American Physical Society, 2003)
      Using first-principles density functional calculations we showed that quantum structures can be generated on a single carbon nanotube by modulating the adsorption of hydrogen atoms. The band gap of the hydrogen-free zone ...
    • Initial stages of Pt growth on Ge (001) studied by scanning tunneling microscopy and density functional theory 

      Gurlu, O.; Zandvliet, H. J. W.; Poelsema, B.; Dag, S.; Çıracı, Salim (American Physical Society, 2004)
      We have studied the initial stages of submonolayer Pt growth on the Ge(001). We have observed several stable and meta-stable adsorption configurations of Pt atoms at various temperatures. Calculations indicate relatively ...
    • Point normal metal-superconductor (NS) contact in nonballistic regime 

      Askerzade, İ. N.; Kulik, Igor Orestovich (World Scientific Publishing, 2003)
      We analyze the point NS contact conductivity taking into account the depression of superconductivity at high-injection current density and Andreev reflection at the adaptive NS boundary. The dependence of the excess current ...
    • Reduced density matrix approach to phononic dissipation in friction 

      Özpineci, A.; Leitner, D. M.; Çıracı, Salim (2000)
      Understanding mechanisms for energy dissipation from nanoparticles in contact with large samples is a central problem in describing friction microscopically. Calculation of the reduced density matrix appears to be the most ...
    • Role of the environmental spectrum in the decoherence and dephasing of multilevel quantum systems 

      Hakioǧlu T.; Savran, K. (The American Physical Society, 2005)
      We examine the effect of multilevels on decoherence and dephasing properties of a quantum system consisting of a nonideal two level subspace, identified as the qubit, and a finite set of higher energy levels above this ...
    • Spin-dependent analysis of two-dimensional electron liquids 

      Bulutay, C.; Tanatar, Bilal (The American Physical Society, 2002)
      Two-dimensional electron liquid (2D EL) at full Fermi degeneracy is revisited, giving special attention to the spin-polarization effects. First, we extend the recently proposed classical-map hypernetted-chain (CHNC) technique ...
    • Structure of aluminum atomic chains 

      Sen, P.; Çıracı, Salim; Buldum, A.; Batra, I. P. (American Physical Society, 2001)
      First-principles density-functional calculations reveal that aluminum can form planar chains in zigzag and ladder structures. The most stable one has equilateral triangular geometry with four nearest neighbors; the other ...
    • Te covered Si(001): a variable surface reconstruction 

      Sen, P.; Çıracı, Salim; Batra, I. P.; Grein, C. H. (American Physical Society, 2001)
      At a given temperature, clean and adatom covered silicon surfaces usually exhibit well-defined reconstruction patterns. Our finite temperature ab initio molecular dynamics calculations show that the tellurium covered Si(001) ...
    • Theoretical study of crossed and parallel carbon nanotube junctions and three-dimensional grid structures 

      Dag, S.; Senger, R. T.; Çıracı, Salim (American Physical Society, 2004)
      This work presents a first-principles study of parallel and crossed junctions of single-wall carbon nanotubes (SWNT). The crossed junctions are modeled by two-dimensional grids of zigzag SWNTs. The atomic and electronic ...
    • Theoretical study of Ga-based nanowires and the interaction of Ga with single-wall carbon nanotubes 

      Durgun, E.; Dag, S.; Çıracı, Salim (American Physical Society, 2004)
      Gallium displays physical properties which can make it a potential element to produce metallic nanowires and high-conducting interconnects in nanoelectronics. Using first-principles pseudopotential plane method we showed ...