Browsing by Author "Senger, R. T."
Now showing items 1-20 of 35
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Ab-initio electron transport calculations of carbon based string structures
Tongay, S.; Senger, R. T.; Dag, S.; Çıracı, Salim (American Physical Society, 2004)The new stable structures of carbon-based strings and their unusual electronic transport properties were discussed. Total energy and electronic structure calculations using first principles pseudopotential plane wave method ... -
Atomic and electronic structure of carbon strings
Tongay, S.; Dag, S.; Durgun, Engin; Senger, R. T.; Çıracı, Salim (IOP Publishing Ltd., 2005)This paper presents an extensive study of various string and tubular structures formed by carbon atomic chains. Our study is based on first-principles pseudopotential plane wave and finite-temperature ab initio molecular ... -
Atomic chains of group-IV elements and III-V and II-VI binary compounds studied by a first-principles pseudopotential method
Senger, R. T.; Tongay, S.; Durgun, Engin; Çıracı, Salim (American Physical Society, 2005)Using the first-principles plane wave pseudopotential method we have studied structural, electronic, and transport properties of atomic chains of group-IV elements and group III-V and group II-VI binary compounds. Several ... -
Bilayer SnS2: tunable stacking sequence by charging and loading pressure
Bacaksiz, C.; Cahangirov, S.; Rubio, A.; Senger, R. T.; Peeters, F. M.; Sahin, H. (American Physical Society, 2016-03)Employing density functional theory-based methods, we investigate monolayer and bilayer structures of hexagonal SnS2, which is a recently synthesized monolayer metal dichalcogenide. Comparison of the 1H and 1T phases of ... -
Binding energies of excitons in II-VI compound-semiconductor based quantum well structures
Senger, R. T.; Bajaj, K. K. (Wiley - V C H Verlag GmbH & Co., 2004)We present a brief description of the calculation of the variation of the binding energy of the heavy-hole exciton as a function of well width in quantum well structures composed of II-VI compound semiconductors including ... -
Carbon string structures: First-principles calculations of quantum conductance
Senger, R. T.; Tongay, S.; Dag, S.; Durgun, Engin; Çıracı, Salim (American Physical Society, 2005)Carbon forms various nanostructures based on the monatomic chains or strings which show transport properties of fundamental and technological interest. We have carried out first-principles quantum conductance calculations ... -
Chiral single-wall gold nanotubes
Senger, R. T.; Dag, S.; Çıracı, Salim (American Physical Society, 2004)The formation of freestanding and tip-suspended chiral-wall (n,m) nanotubes, which were composed of helical atomic strands, from gold atoms was investigated using first-principles calculations, where (n,m) notation defines ... -
Determination of energy-band offsets between GaN and AlN using excitonic luminescence transition in AlGaN alloys
Westmeyer, A. N.; Mahajan, S.; Bajaj, K. K.; Lin J. Y.; Jiang, H. X.; Koleske, D. D.; Senger, R. T. (American Institute of PhysicsA I P Publishing LLC, 2006)We report the determination of the energy-band offsets between GaN and AlN using the linewidth (full width at half maximum) of an extremely sharp excitonic luminescence transition in Alx Ga1-x N alloy with x=0.18 at 10 K. ... -
Dynamics of phononic dissipation at the atomic scale: Dependence on internal degrees of freedom
Sevinçli, H.; Mukhopadhyay, S.; Senger, R. T.; Çıracı, Salim (American Physical Society, 2007)Dynamics of dissipation local vibrations to the surrounding substrate is a key issue in friction between sliding surfaces as well as in boundary lubrication. We consider a model system consisting of an excited nano-particle ... -
Energy and mass of 3D and 2D polarons in the overall range of the electron-phonon coupling strength
Ercelebi, A.; Senger, R. T. (Institute of Physics Publishing Ltd., 1994)The ground-state characterization of the polaron problem is retrieved within the framework of a variational scheme proposed previously by Devreese et al for the bound polaron. The formulation is based on the standard ... -
Energy-transfer rate in a double-quantum-well system due to Coulomb coupling
Senger, R. T.; Tanatar, Bilal (Elsevier, 2002)We study the energy-transfer rate for electrons in a double-quantum-well structure, where the layers are coupled through screened Coulomb interactions. The energy-transfer rate between the layers (similar to the Coulomb ... -
First-principles calculations of spin-dependent conductance of graphene flakes
Şahin, H.; Senger, R. T. (The American Physical Society, 2008)Using ab initio density-functional theory and quantum transport calculations based on nonequilibrium Green's function formalism we study structural, electronic, and transport properties of hydrogen-terminated short graphene ... -
Ground-state description of quasi-one-dimensional polarons with arbitrary electron-phonon coupling strength
Erçelebi, A.; Senger, R. T. (American Physical Society, 1996)We consider the interaction of a confined electron with bulk polar-optical phonons in a cylindrical quantum well wire with infinite boundary potential. Expressions for the polaron self-energy and mass are derived within a ... -
Half-metallic properties of atomic chains of carbon-transition-metal compounds
Dag, S.; Tongay, S.; Yildirim, T.; Durgun, Engin; Senger, R. T.; Fong, C. Y.; Çıracı, Salim (American Physical Society, 2005)We found that magnetic ground state of one-dimensional atomic chains of carbon-transition-metal compounds exhibit half-metallic properties. They are semiconductors for one spin direction, but show metallic properties for ... -
Hartree-Fock approximation of bipolaron state in quantum dots and wires
Senger, R. T.; Kozal, B.; Chatterjee, A.; Erçelebi, A. (Springer, 2010)The bipolaronic ground state of two electrons in a spherical quantum dot or a quantum wire with parabolic boundaries is studied in the strong electron-phonon coupling regime. We introduce a variational wave function that ... -
Layer-and strain-dependent optoelectronic properties of hexagonal AIN
Kecik, D.; Bacaksiz, C.; Senger, R. T.; Durgun, Engin (American Physical Society, 2015)Motivated by the recent synthesis of layered hexagonal aluminum nitride (h-AlN), we investigate its layer- and strain-dependent electronic and optical properties by using first-principles methods. Monolayer h-AlN is a ... -
Magnetic field effects on an electron near an impenetrable dielectric surface
Saqqa, B.; Senger, R. T.; Erçelebi, A. (1996)The interaction of an extrinsic electron with the surface optical modes of a semi-infinite medium is retrieved under the effect of a weak magnetic field. It is observed that for an electron in a bound state near the surface, ... -
Monolayer honeycomb structures of group-IV elements and III-V binary compounds: First-principles calculations
Şahin, H.; Cahangirov, S.; Topsakal, M.; Bekaroglu, E.; Akturk, E.; Senger, R. T.; Çıracı, Salim (American Physical Society, 2009)Using first-principles plane-wave calculations, we investigate two-dimensional (2D) honeycomb structure of group-IV elements and their binary compounds as well as the compounds of group III-V elements. Based on structure ... -
Monte Carlo simulation of localization dynamics of excitons in ZnO and CdZnO quantum well structures
Makino, T.; Saito, K.; Ohtomo, A.; Kawasaki, M.; Senger, R. T.; Bajaj, K. K. (American Institute of Physics, 2006)Localization dynamics of excitons was studied for ZnOMgZnO and CdZnOMgZnO quantum wells (QWs). The experimental photoluminescence (PL) and absorption data were compared with the results of Monte Carlo simulation in which ... -
Nanospintronic properties of carbon-cobalt atomic chains
Durgun, Engin; Senger, R. T.; Mehrez, H.; Dag, S.; Çıracı, Salim (EDP Sciences, 2006)Periodic atom chains of carbon-cobalt compounds, (CnCo) ∞, comprise both conducting and insulating electronic properties simultaneously depending on the spin type of electrons, and hence are half-metals. Their band gap and ...