Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Article Citation - WoS: 69Citation - Scopus: 90Structural Stability and Energetics of Single-Walled Carbon Nanotubes Under Uniaxial Strain(Amer Physical Soc, 2003) Ozdogan, C; Dereli, GA (10x10) single-walled carbon nanotube consisting of 400 atoms with 20 layers is simulated under tensile loading using our developed O(N) parallel tight-binding molecular-dynamics algorithms. It is observed that the simulated carbon nanotube is able to carry the strain up to 122% of the relaxed tube length in elongation and up to 93% for compression. Young's modulus, tensile strength, and the Poisson ratio are calculated and the values found are 0.311 TPa, 4.92 GPa, and 0.287, respectively. The stress-strain curve is obtained. The elastic limit is observed at a strain rate of 0.09 while the breaking point is at 0.23. The frequency of vibration for the pristine (10x10) carbon nanotube in the radial direction is 4.71x10(3) GHz and it is sensitive to the strain rate.Article Citation - WoS: 1Citation - Scopus: 1Nonlinear Realization of Pure N=4,d=5 Supergravity -: Art. No. 105013(Amer Physical Soc, 2005) Yilmaz, NTWe perform the nonlinear realization or the coset formulation of the pure N=4, D=5 supergravity. We derive the Lie superalgebra which parameterizes a coset map whose induced Cartan-Maurer form produces the bosonic field equations of the pure N=4, D=5 supergravity by canonically satisfying the Cartan-Maurer equation. We also obtain the first-order field equations of the theory as a twisted self-duality condition for the Cartan-Maurer form within the geometrical framework of the coset construction.Article Citation - WoS: 23Citation - Scopus: 23Entanglement of Optical and Microcavity Modes by Means of an Optoelectronic System(Amer Physical Soc, 2019) Salmanogli, Ahmad; Gokcen, Dincer; Gecim, H. SelcukEntanglement between optical and microwave cavity modes is a critical issue in illumination systems. Optomechanical systems are utilized to introduce coupling between the optical and microwave cavity modes. However, due to some restrictions of the optomechanical system, especially sensitivity to the thermal photon noise at room temperature, an alternative optoelectronic system is designed to address the problem. We study a method by which it may be possible to remove the mechanical part of the previous systems to minimize the thermally generated photons. Unlike optomechanical systems, in our system, the optical mode is directly coupled to the microwave cavity mode through the optoelectronic elements without employing any mechanical parts. The utilized approach leads to generating the entangled modes at room temperature. For this purpose, the dynamics of the motion of the optoelectronic system is theoretically derived using the Heisenberg-Langevin equations from which one can calculate the coupling between optical and microwave cavity modes. The direct coupling between the optical and microwave cavity modes is the most important feature and is achieved through the combination of the photodetector and a Varactor diode. Hence, by controlling the photodetector current, that is, the photocurrent, depending on the optical cavity incident wave and the Varactor diode-biased voltage, the coupling between the optical and microwave cavity modes is established. The voltage across the Varactor diode also depends on the generated photocurrent. Consequently, our results show that the coupled modes are entangled at room temperature without the requirement for any mechanical parts.Article Citation - WoS: 210Citation - Scopus: 219Stability of Edge States and Edge Magnetism in Graphene Nanoribbons(Amer Physical Soc, 2011) Ozdogan, Cem; Quandt, Alexander; Fehske, Holger; Kunstmann, JensWe critically discuss the stability of edge states and edge magnetism in zigzag edge graphene nanoribbons (ZGNRs). We point out that magnetic edge states might not exist in real systems and show that there are at least three very natural mechanisms-edge reconstruction, edge passivation, and edge closure-which dramatically reduce the effect of edge states in ZGNRs or even totally eliminate them. Even if systems with magnetic edge states could be made, the intrinsic magnetism would not be stable at room temperature. Charge doping and the presence of edge defects further destabilize the intrinsic magnetism of such systems.