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    Binding energy of a hydrogenic impurity in a coaxial quantum wire with an insulator layer
    (Academic Press Ltd- Elsevier Science Ltd, 2017) Kes, H.; Bilekkaya, A.; Aktas, S.; Okan, S. E.
    The electronic properties of a coaxial cylindrical quantum well-barrier system constituted about an central insulating wire were determined under an external electric field. The model wire, inside to outside, was considered to be layered as AlAs/GaAs/Alx1Ga1-xAs/GaAs/Alx2Ga1-x2As. Within the framework of the effective mass approximation, the binding energy of a hydrogenic impurity is calculated by using the combination of the fourth-order Runge-Kutta method and variational approaches. The binding energy exhibits sharp changes depending on the impurity position and the geometrical parameters of the structure such as the well widths of the GaAs wires and the height and thickness of the barrier constituted by Alx1Ga1-x1 As. The binding energy of the electron was found to be independent from the impurity position for the specific widths of the well wires. Also, the barrier properties appeared as very effective parameters in controlling the probability distribution of the electron. (C) 2017 Elsevier Ltd. All rights reserved.
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    Control of a resonant tunneling structure by intense laser fields
    (Academic Press Ltd- Elsevier Science Ltd, 2016) Aktas, S.; Kes, H.; Boz, F. K.; Okan, S. E.
    The intense laser field effects on a resonant tunneling structure were studied using computational methods. The considered structure was a GaAs/InxGa1-xAs/Al0.3Ga0.7As/InyGa1-yAs/AlAs/GaAs well-barrier system. In the presence of intense laser fields, the transmission coefficient and the dwell time of the structure were calculated depending on the depth and the width of InGaAs wells. It was shown that an intense laser field provides full control on the performance of the device as the geometrical restrictions on the resonant tunneling conditions overcome. Also, the choice of the resonant energy value becomes possible depending on the field strength. (C) 2016 Elsevier Ltd. All rights reserved.
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    Effective interatomic pair potentials for liquid silver-tin alloys
    (Amer Inst Physics, 2007) Dalgic, S. Senturk; Kes, H.
    The transferability of the local evanescent core (EC) pseudopotential to liquid AgSn binary alloys have been tested. The effective interatomic pair potentials derived from the evanescent core electron-ion potential which was constructed by Nogueira and co-workers have been calculated using the second order perturbation theory. The structural properties of liquid Ag-Sn alloys at different compositions of tin have obtained using the Variational Modified Hypernetted Chain (VMHNC) integral equation theory of liquids. The results for the partial structure factors and total structure factors near their melting have been compared with experimental data. The computed structural characteristics exhibit the correct trends with experiment. It has been shown the ability of the universal density dependent version of the EC potential to be used in the case of liquid Ag-Sn simple metals and metal alloys. The charge transferred between atoms have also been investigated.
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    The excitons in infinite potential centered multilayered coaxial quantum wire and the magnetic field effects on their properties
    (Academic Press Ltd- Elsevier Science Ltd, 2020) Kes, H.; Okan, S. E.; Aktas, S.
    The exciton properties in a multilayered coaxial cylindrical quantum wire layered as AlAs/GaAs/ AlxGa1-xAs/GaAs/ AlxGa1-xAs are investigated. The exciton binding energies are obtained as a functions of the thicknesses of the GaAs well wires and the barrier wires formed by AlxGa1-xAs keeping the total radius of the structure constant and considering two by two variation of those. The binding energies has only one minimum for each variation and they all have approximate minimum binding energy values for their certain set of thicknesses. The magnetic field effects on the binding energies are also reported. The external magnetic field produces noticeably different effects on the electronic properties of the heavy hole and light hole excitons. The magnetic field can be shifted smaller strengths to obtain the minimum binding energy if the radius of the insulator wire in the center of the structure is increased.